Initial import.

The Net::Http adapter was inspired from:

  https://github.com/recurly/recurly-client-ruby

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
Merge branch 'master' of github.com:killbill/killbill-client-ruby

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>

Conflicts:
	README.md