Release v0.3.0

Changelog:
  Implement Display for Storyboard
  Move tests to end of files
  Remove license header
  Add basic IntervalMap container
  feat: Add tests & fix bug
  format code with cargo fmt
  Preparing for GitHub migration
  Updating README.md
  easing: use Option<> rather than EasingParsingError
  docs: more information on intervalmap and storyboard
  layer: add Overlay layer
  misc: add code of conduct

The full changelog is available at the following link:
v0.2.0...v0.3.0

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "osb"
-version = "0.2.0"
+version = "0.3.0"
 authors = ["Asperatus <[email protected]>"]
 edition = "2018"
 description = "A fast, fully-fledged, scalable and secure implementation of the .osb storyboard file format"