This was missed when dropping the null-termination from our string
types. An explicit null byte can still be placed anywhere in a string if
desired, but there's no reason to stick one at the end of every string
constant.

Closes #2569

Closes #5283

Closes #13042.

Favor using '*' instead

It's now in the prelude.

Closes #12771

This commit goes back to using `gensym` to generate unique tokens to put into
the names of closures, allowing closures to be able to get demangled in
backtraces.

Closes #12400

Closes #7141.

This leverages the new hashing framework and hashmap implementation to provide a
much speedier hashing algorithm for node ids and def ids. The hash algorithm
used is currentl FNV hashing, but it's quite easy to swap out.

I originally implemented hashing as the identity function, but this actually
ended up in slowing down rustc compiling libstd from 8s to 13s. I would suspect
that this is a result of a large number of collisions.

With FNV hashing, we get these timings (compiling with --no-trans, in seconds):

|           |  before  |  after  |
|-----------|---------:|--------:|
| libstd    |   8.324  |  6.703  |
| stdtest   |  47.674  | 46.857  |
| libsyntax |   9.918  |  8.400  |

These two containers are indeed collections, so their place is in
libcollections, not in libstd. There will always be a hash map as part of the
standard distribution of Rust, but by moving it out of the standard library it
makes libstd that much more portable to more platforms and environments.

This conveniently also removes the stuttering of 'std::hashmap::HashMap',
although 'collections::HashMap' is only one character shorter.

Added allow(non_camel_case_types) to librustc where necesary

Tried to fix problems with non_camel_case_types outside rustc

fixed failing tests

Docs updated

Moved #[allow(non_camel_case_types)] a level higher.

markdown.rs reverted

Fixed timer that was failing tests

Fixed another timer

These can all be done by implicit or explicit &T -> *T casts, which are
more restricted and so are safer.

Error messages cleaned in librustc/middle

Error messages cleaned in libsyntax

Error messages cleaned in libsyntax more agressively

Error messages cleaned in librustc more aggressively

Fixed affected tests

Fixed other failing tests

Last failing tests fixed

Reflection is now the only user of type descriptors. Uses of drop glue
no longer cause a type descriptor to be generated.

of builtin bounds.

Fixes #10834.
Fixes #11385.
cc #5922.