replaced GeventRPC* classes with generic GreenRPC* classes, added green compatible netcall.futures.Future
made green tests active only if there is a corresponding module available
updated README
added utils.green_device, cleaned up utils
updated existing examples, added new examples
bumped version to 0.3, updated project keywords
added missing pebble dependency to setup.py
fixed a relative import bug in netcall.futures
Merge branch 'upstream/master'

Conflicts:
	README.md
	netcall/green/client.py
	netcall/green/service.py
	netcall/threading/client.py
	tests/base.py