Replace GPIO with Gpio

Begin to bring things into complicance with the Rust style guide.
Merge pull request #208 from bgamari/style

Replace GPIO with Gpio
Merge branch 'master' of https://github.com/hackndev/zinc

Conflicts:
	src/zinc/hal/k20/pin.rs
	src/zinc/hal/lpc17xx/pin.rs
Renamed fail! to panic!
Updated parsers to follow new libsyntax naming
Renamed fail_fmt to panic_fmt
Renamed missing_doc to missing_docs
Renamed unused_variable to unused_variables
Merge pull request #210 from farcaller/fix-nightly

Various fixes to unbreak master
Fix warning about redundant patterns

/Users/ilya/Code/rust/zinc/src/ioreg/builder/utils.rs:95:23: 95:45 warning: the `opt_name:` in this pattern is redundant and can be removed, #[warn(non_shorthand_field_patterns)] on by default
/Users/ilya/Code/rust/zinc/src/ioreg/builder/utils.rs:95     node::EnumField { opt_name: ref opt_name, ..} => {
                                                                               ^~~~~~~~~~~~~~~~~~~~~~
/Users/ilya/Code/rust/zinc/src/ioreg/builder/register.rs:63:23: 63:45 warning: the `variants:` in this pattern is redundant and can be removed, #[warn(non_shorthand_field_patterns)] on by default
/Users/ilya/Code/rust/zinc/src/ioreg/builder/register.rs:63     node::EnumField { variants: ref variants, .. } => {
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~
Cleanup unused import warning on test
Fix a few miscelaneous warnings
Merge pull request #211 from errordeveloper/master

Fix most warnings
Collections traits had been removed (rust-lang/rust@21ac985af)
Merge pull request #214 from errordeveloper/master

Collections traits had been removed (rust-lang/rust@21ac985af)
Driver for the Hitachi HD44780U dot matrix LCD controller

- Only 4bit parallel interface supported for now
- Write-only operation (RW pin should be connected to ground or held low)
- 1 or 2 line LCDs supported with 5x8 or 5x10 dot fonts.
- Support for creating custom characters.
Merge pull request #215 from simias/lcd-pr

Driver for the Hitachi HD44780U dot matrix LCD controller
Always add debug symbols
Removed double -g in tests
Merge pull request #216 from farcaller/enable-debug

Always add debug symbols