Merge pull request #25 from Tom-Ski/master

Mavenized/Gradle'ized so we can push snapshots and releases.
Adds family filtering
Updates TODO.md
fixed publish.gradle, ready to release snapshots/releases
Iterate version
Update readme with maven info
Doesn't need snapshot in version name
Changes BitSet for Libgdx Bits class to move towards GWT compatibility
Adds Apache license header to source files and AUTHORS file
fixed Java 8 issues with doclint throwing errors
Simplifies some hashCode() methods
Ashley depends on gdx-core (1.2.0)
ImmutableArray and ImmutableIntMap are wrappers of gdx's Array and IntMap
Update README.md
Adds ashley_gwt.gwt.xml file for GWT compatibility
Merge branch 'master' of github.com:libgdx/ashley
Use Gwt safe casts and ClassReflection methods