@brson. Also fix a few documentation bugs.

directory to be the parent of the current-current directory,
instead of changing to the tmp directory, which was causing
issues with OS X and its /tmp => /private/tmp symlink.

mentioned in #2625.

This change makes the module more oriented around
Process values instead of having to deal with process ids
directly.

Apart from issues mentioned in #2625, other changes include:
- Changing the naming to be more consistent - Process/process
  is now used instead of a mixture of Program/program and
  Process/process.
- More docs/tests.

Some io/scheduler related issues remain (mentioned in #2625).

Whatever it was, it is no longer a problem here.

Fixes #6697

There was some before, but now we have a big header, as well as
lots of individual bits of documentation.

This indents all but the first line of multi-line annotations for individual enum variants with four spaces so that pandoc will recognize everything as belonging to the same list item.

Since that introduces `<p>` tags for some list items, I've gone ahead and inserted blank lines after each list item so that consistently get `<p>` tags for all `<li>`s documenting variants. It's a bit less compact now but still tolerable, I think.

There was some before, but now we have a big header, as well as
lots of individual bits of documentation.

This marks `&mut` function arguments with the `noalias` attribute. Since the borrow checker enforces this property, this is worth doing.

I'm not sure if the place I'm doing it in is ideal, but it generates the correct code.

Closes #6350

This indents all but the first line of multi-line annotations for
individual enum variants with four spaces so that pandoc will
recognize everything as belonging to the same list item.

Since that introduces `<p>` tags for some list items, I've gone ahead
and inserted blank lines after each list item so that consistently
get `<p>` tags for all `<li>`s documenting variants. It's a bit less
compact now but still tolerable, I think.

r? @brson (Yes, this did happen in real life...)

...and don't treat Path("/") like Path("").

(Yes, this did happen in real life...)

Changes the int/uint modules to all use macros instead of using the `merge` attribute. It would be nice to have #4375 resolved as well for this, but that can probably come at a later date.

Closes #4219.

This pull request is more of an RFC than a finished implementation.

It adds some basic atomic types, with an interface modelled off of C++11's atomic types.

It also adds free functions that provide a slightly nicer interface for atomic operations, though they are unsafe because there isn't a way to be generic over "word-sized" types.

See also #5042

Currently, keywords are stored in hashsets that are recreated for every
Parser instance, which is quite expensive since macro expansion creates
lots of them. Additionally, the parser functions that look for a keyword
currently accept a string and have a runtime check to validate that they
actually received a keyword.

By creating an enum for the keywords and inserting them into the
ident interner, we can avoid the creation of the hashsets and get static
checks for the keywords.

For libstd, this cuts the parse+expansion part from ~2.6s to ~1.6s.

Currently, keywords are stored in hashsets that are recreated for every
Parser instance, which is quite expensive since macro expansion creates
lots of them. Additionally, the parser functions that look for a keyword
currently accept a string and have a runtime check to validate that they
actually received a keyword.

By creating an enum for the keywords and inserting them into the
ident interner, we can avoid the creation of the hashsets and get static
checks for the keywords.

For libstd, this cuts the parse+expansion part from ~2.6s to ~1.6s.

This updates the bundled linenoise library, and explicitly builds it with UTF8 support. This way rusti correctly handles utf8 characters when doing line operations.

Closes #6681

Scripts need to know if the tests pass or the program ran correctly.

Among other things, this suppresses a spurious unused import warning in the compiler right now.

* Remove clone and get functions from ARC.
* Update the tests and bench. 

Rust is now preferring methods over functions and there is no legacy with ARC

Scripts need to know if the tests pass or the program ran correctly.

As discussed with @brson on IRC:

This lets us use #ifdefs to determine which stage of the build we happen
to be in, which is useful in the event we need to make changes to rustrt
that are incompatible with the code generated by a stage0 rustc.

Example of the _RUST_STAGEN flag in action here: https://gist.github.com/thomaslee/5641890

I'm not sure what tests for this change should look like, so please advise if I need to do some work around that.

There's currently a function in the lexer that rejects a line comment that is all slashes from being a doc comment. I think the intention was that you could draw boxes,

    /////////////
    // like so //
    /////////////

Since a line doc comment split up over multiple paragraphs will have a "blank" line that is just /// between the paragraphs, that would get mistaken for a box segment, lexed as a regular comment, and go missing from the sequence of doc comment attributes before they were reassembled by rustdoc into markdown input.

I figure the best plan here is to just declare that a comment that is exactly `///` is a doc comment after all, and to only omit comments with four slashes or more, which is what this commit implements. Can't really draw boxes that narrow, anyway.