making BuildHelper.getTransitiveDependencies method more flexible
fixing artifacts filtering in case no arguments provided
Merge master into improving-build-helper-api

Conflicts:
	src/main/java/com/jayway/maven/plugins/android/common/BuildHelper.java
	src/main/java/com/jayway/maven/plugins/android/phase01generatesources/GenerateSourcesMojo.java
	src/main/java/com/jayway/maven/plugins/android/phase01generatesources/ResourceClassGenerator.java
moving other classes to new BuildHelper API
Merge pull request #294 from marchelo/improving-build-helper-api

making BuildHelper.getTransitiveDependencies method more flexible