Added a method to build python/kivy projects using buildozer.
There is an outdated implementation for kivy buids already in the server. It wouldnt work with actuall p4a version.
The new implementation uses buildozer (also a kivy initiated project) that automates builds using p4a.
A user will have to specify buildozer=yes in the build section of his metadata file. And supply ANDROID_HOME and ANDROID_NDK.