Cargo.toml: update dependencies, bump version 0.7.0
Cargo.toml: update dependencies, bump version 0.7.0

Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2,xsleonard/rust-sdl2_image,AngryLawyer/rust-sdl2,Machtan/rust-sdl2_image,Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2,vadixidav/rust-sdl2,Cobrand/rust-sdl2,crumblingstatue/rust-sdl2_image,Rust-SDL2/rust-sdl2