Merge pull request #3 from nielsegberts/master

Obsolete syntax and fix for segfault on exit
Fix obsolete syntax (to Rust 0.6).
Fix unused libraries compiler warnings.
Trait visiblity. Couldn't use length() from main.rs.
Fix pointer mismatches.
Update README.md for compiler version and how to get rust-sdl.
Added support for rustpkg
Updated readme on how to build using rustpkg