_patch_application_sources breaks from __future__ imports

[LilyFoote]

The method _patch_application_sources in buildozer/__init__.py prepends main.py with:

import sys, os; sys.path = [os.path.join(os.path.dirname(__file__), "_applibs")] + sys.path

This causes a syntax error if the original first line started with a from __future__ import statement, e.g.:

from __future__ import division

SyntaxError: ('from __future__ imports must occur at the beginning of the file', ('/home/ian/life/.buildozer/android/app/main.py', 2, None, 'from __future__ import division\n'))

[tshirtman]

As discussed, that's indeed an issue, and the correct solution in the current context is non-trivial, would be better to change how the packages are added, maybe adding the content of _applibs to the shipped pythonpackages?