Release version v0.12.1

Release version v0.12.0

Bump tcod to 0.11.0

Bump tcod to 0.10.0 and tcod_sys to 4.0.1

Merge pull request tomassedovic#214 from tomassedovic/gcc

Use gcc crate in tcod_sys' build script

Bump tcod to 0.8.1

Bump tcod to 0.8.0 and tcod_sys to 3.0.0

Bump tcod to 0.7.0 and tcod_sys to 2.0.11

Bump tcod to 0.6.0 and tcod_sys to 2.0.11

Bump tcod to 0.5.5 and tcod_sys to 2.0.10