Bug 924133 - Remove Android WebApps preprocessing. r=wesj

The existing code complicates the build system and IDE integration.
This keeps most of the flexibility while simplifying the build system.
Bug 923306 - Add JAVA_JAR_TARGETS. r=glandium
Bug 923306 - Make annotationProcessors build with -Xlint:all. r=ckitching
Bug 923306 - Build annotationProcessors with JAVA_JAR_TARGETS. r=glandium