Merge pull request #87 from itdaniher/master

fixed c_str semantics
Use externfn macro.
Update demo to run on main thread.
Adjust linking SDL_image/mixer for macos.
Merge pull request #89 from luqmana/up

Updates
fixed README.md for compiling demo, and patched audio.rs
fixed instruction to compile the demo
Merge pull request #90 from Eskatrem/master

quick patches
Remove start.

This is no longer necessary with the new scheduler.
Merge pull request #91 from pcwalton/remove-start

Remove start.
Use `== 0` instead of `as bool`
Merge pull request #92 from jsanders/fix_as_bool

Use `== 0` instead of `as bool`
Removed unneccesary call to SDL::Start
Removed broken link args + some other cleanup
Added no_main. Fixes #93
Merge pull request #95 from sfackler/link

Removed broken link args + some other cleanup
Make demo link properly.
Merge pull request #97 from jdm/demofix

Make demo link properly.
Updated to latest Master
Switch from std::rand::RngUtil to std::rand::Rng.

Due to Rust commit fb923c7d3f8b.