Zoltan is having a few issues with auto-provisioning in recent XA.
* XA installs a new system mono, which can break all kinds of stuff.
* Also, if I have two xa trees, will they keep installing their own mono versions
back to back ?
* doing make mono will generate a cache file. Doing make clean in builds/ doesn't delete it, so doing make all in builds/ will use that instead of doing a rebuild.
* The .stamp file for android-sdk-tool is created even if the reset fails for some
reason, leading to strange bugs later on.
* The reset target for android-sdk-tool should be called 'reset-android-sdk-tool' instead of 'reset-android-sdks'.