Remove unnecessary "enabled" default option

The config.RepoConf.enabled declaration was causing yum to disable repos that did not have enabled=1 specified, which is the opposite of normal yum behavior.

This had the effect of disabling the default CentOS repositories (which are installed by the centos-release package, but do not specify enabled=1)
Bump version to 0.2.3
Merge pull request #7 from diablomedia/master

Don't change yum's default behavior (enable=1). Thanks @aripringle.