Update to the last rust-nightly.

Version of rustc: 0.12.0-pre-nightly (2e92c67dc 2014-08-28 23:56:20 +0000).
Merge pull request #217 from sebcrozet/master

Update to the last rust-nightly.
fix/ignore doc-tests
Merge pull request #218 from csherratt/master

fix/ignore doc-tests
Use a more comprehensive set of derivings for most things
Fix FFI module

Allow for bad style, and set C representation hint
Remove use of deprecated to_option
Fix warning in example
Merge pull request #220 from cmr/derive-show

Various small fixes
Make get_proc_address less error-prone

This solves the (fairly common) error of forgetting to make a context current
before trying to load GL function pointers. It accomplishes this by using
moving get_proc_address to Window and using glfwGetCurrentContext to check if
that Window is current before actually loading the function. It adds a
Glfw::get_proc_address_raw that is as today but with a debug assertion that
there is a currently bound context.

The method on Window should be used, generally, though it will incur a slight
performance penalty (adds a branch, and glfwGetCurrentContext will do a TLS
fetch).
Merge pull request #221 from cmr/derive-show

Make get_proc_address less error-prone
Update to nightly
Merge pull request #224 from cmr/rustup-9/14/2014

Update to nightly
Update for Gc -> P change in libsyntax
Merge pull request #226 from tomjakubowski/fix-for-p

Update for Gc -> P change in libsyntax
Switch to Cargoified libglfw and link statically.
Merge pull request #219 from metajack/cargo-libglfw

Switch to Cargoified libglfw and link statically.
Merge remote-tracking branch 'upstream/master' into rustup

Conflicts:
	src/lib.rs
	src/link_glfw/lib.rs
Merge pull request #23 from servo/rustup

Rust upgrade