Closes #2255

Closes #2185

Figure the rest out in the parser

Use lookahead in the parser

In the "not all paths return" error message, typestate was printing
the AST type from the fn decl, not the ty::t type. This ended in tears
when the AST return type was "ty_infer". Now it looks up the function node
ID's type and uses util::ppaux::ty_to_str instead.

Closes #2163.

ignore high_level_loop tests in std

until race issue with (most likely) refcount scheme is sorted out

.. leveraging std::uv, we have:
timer::delayed_send - send a value over a provided channel after the
timeout has passed
timer::sleep - block the current task for the specified period

both of these fns (and everything that goes in timer.rs) leverage the
uv_timer_* API

.. fixes issue, in previous commit, with global loop test hanging on
32bit linux (this was because the struct was too small, so (presumably),
the data member was garbled.. yippy)

- moved global loop tests, as well.. will add tests in uv_hl that encompass
rolling your own high_level_loop via uv::hl::run_high_level_loop()
- also whitespace cleanups and misc warning cleanup..
- doesn't work on 32bit linux

.. seeing an occasional valgrind/barf spew on some invalid read/writes..
need to investigate further.. i think its related to my poor citizen
conduct, re: pointers stashed in rust_kernel..

- starting/stoping the loop based on client work is functioning, correctly
- the issue appears to be that, when the process is about to exit, the
signal to let weak tasks know that they need to exit isn't getting fired.