Bug 933300 - Write preprocessed Fennec code into generated/org/mozilla/*. r=glandium

This writes source with preprocessed package names into
generated/org/mozilla/{firefox,firefox_beta,fennec,fennec_$USERID},
and the other preprocessed source into generated/org/mozilla/gecko.

This layout matches the Java package hierarchy and is what IDEs expect
when including $OBJDIR/generated as a source directory.

--HG--
extra : rebase_source : 5cc397e6808d21a662c1f718ef49ee148c15e465