[#4] Install git before trying to use it; add a unit test for cloudfoundry_source so that hopefully we can catch other problems.

Unfortunately git is installed by test-kitchen itself so we wouldn't have noticed anyway.
Cleanup: do not create bundler directories ourselves, bundler will.

Not sure why at some point in the past I thought it was necessary; maybe some bug that I've since fixed.
Release 1.3.2: fix missing dependencies.
Adjust includes for Chef 11.
Make sure the test cookbook depends on the cookbook under test, since that affects the order in which Chef 11 includes attribute files.
Add a note to the README listing supported and tested versions of Chef.
Release 1.3.3: improve support for Chef 11.
Bump the default version of ruby to 1.9.3-p392.

p392 fixes a couple of vulnerabilities, and the previous releases also contained security and bug fixes.
Release 1.3.4: bump ruby version.