Just a quick announcement, if you're wanting to upgrade your Android SDK Tools/Platform-tools (at this point, 23.0.2 and 20 respectively), you'll need to be aware that things have changed a bit and building for Android will fail unless you either duplicate or make a symbolic link for zipalign.
The actual location of zipalign is:
adt-bundle-*/sdk/build-tools/19.1.0/zipalign
The expected location is:
adt-bundle-*/sdk/tools/zipalign
Happy Android building.
[Saint]