Allow specifying garden packages in buildozer.spec
Specify cwd for garden cmd. Use --app arg.
Install garden packages listed in buildozer.spec.

Requires local copy of garden script.
Ensure garden script is available.
Merge remote-tracking branch 'origin/garden_requirements' into garden_requirements

Conflicts:
	buildozer/__init__.py
Remove garden script from tools.
Use kivy-garden's version of garden.

Tweak garden_requirements.
Specify version of garden to use.
Use garden version 0.1.1.
Merge branch 'master' into garden_requirements
Use Garden package from PyPI instead of github
implement the `clean` command.
implement the `clean` command.
Delete dist dir if running distribute.sh
Merge branch 'buildozer_clean' of http://github.com/kivy/buildozer into buildozer_clean
rename `clean` to `distclean`
Fixed p4a installation to check correct env var
doc: Documented environment variable checking
Merge pull request #85 from inclement/p4a_dir_fixes

Documented env var checking and fixed a bug in the p4a_dir check
Added realpath modifier to p4a_dir token