merge profile and prosthesis targets
stop building extinct skin directory
reorder/update Makefile help text
add 'test' target to list of phony targets
don't display internal code comment when making adb
only download ADB if we haven't already
don't fail to clean when files to remove don't exist
remove B2G package when cleaning
Merge pull request #512 from mykmelez/makefile-cleanup

clean up Makefile