Added support for chef environment api.

Change formating to jcloud standarts. Added SinceApiVersion annotation to new methods. Removed environmentExists method from api.

Added forgeted serializable name for attributes field of environment
Merge pull request #61 from kulya/master

Ability to work with environments at chef > 0.10.0
There is no need to force the Chef version anymore
Merge pull request #63 from nacx/noforce-chef

There is no need to force the Chef version anymore
Enable properties to configure Chef gems

Added context properties to allow users customize how RubyGems is
installed and also the version of the Chef gems that is installed when
bootstrapping nodes.
Merge pull request #64 from nacx/flexible-chef-gems

Enable properties to configure Chef gems
[maven-release-plugin] prepare release jclouds-chef-1.6.0-alpha.4
[maven-release-plugin] prepare for next development iteration
Merge branch 'upstream-sync' into 2.6