undo extraneous changes
undo more extraneous changes; ifdef more synthapk-specific code
translate variable name from data to argument
remove dependency on WebApps:PreInstall; simplify dependency on WebApps:PostInstall
make more code conditional on MOZ_ANDROID_SYNTHAPKS
make more code conditional on MOZ_ANDROID_SYNTHAPKS
make more code conditional on MOZ_ANDROID_SYNTHAPKS
catch exception unregistering receiver so Fennec doesn't crash
don't pre-install appcache