replace symlink silliness ant required with gradle commands to sign
debug builds with the checked-in (local file) debug keystore. Make
it possible for an environment variable to override in case somebody
wants to use his own.
Build different jni code (into different obj and libs directories) for
the different release/debug and xw4/xw4dbg combinations. This works when
only one build is done, but when doing two some later task tries to put
both multiple same-named libraries into the .apk and so fails. I still
think it's worth adding this to keep from using the wrong binary, but
that needs to be fixed.
cleanNDK just nukes all the directories. Easier than invoking build-ndk
clean...
