Replace Still Maintained status with Travis-CI.

http://stillmaintained.com/ shut down August 1, 2012.
Merge pull request #307 from glennpratt/travis-badge

Replace Still Maintained status with Travis-CI.
fixed cloning of asset references
multiple clones should be additive
Merge branch '1.0.x' into 1.1.x

Conflicts:
	README.md