Add rust-ci
Merge pull request #85 from Indiv0/add-rust-ci

Add rust-ci
Upgraded to latest gfx-rs + Rust
Merge pull request #86 from bvssvni/master

Upgraded to latest gfx-rs + Rust
Upgraded to latest Piston
Merge pull request #87 from bvssvni/master

Upgraded to latest Piston
block_state: fixup ao_face, not only cull_face, when rotating the model.
block_state: adjust expected "above" to match vertices rounded "down".
Differentiate between transparent-solid, opaque and transparent blocks, for AO.
Merge pull request #88 from eddyb/lighting-fixes

Lighting/AO improvements.