Major build script refactoring: Converted into Gradle Multi-project build. Just run gradle from the contributions folder to build all projects (yapg still pending).
Changed antlr* builds to generate sources at build time.
Conflicts:
	contributions/antlrLexer/build.gradle
	contributions/antlrObjects/build.gradle
	contributions/antlrParser/build.gradle
	contributions/antlrTrees/build.gradle
	contributions/build.gradle