Add ability to install rbenv independently

- Can now install rbenv separately. Can be used as a requirement in a
  state for installing rbenv plugins using the git or file states
Fix description of method and whitespace lost
only use token_file if modified within token_expire time
use time.mktime, not time.strftime
implement serializers
expose documentation of serializers
implement aggregation
ensure that str are yaml friendly
document aggregation
added reset tag
a little bit of lint
salt.modules.lxc: fix warning

/cc @mgwilliams
split tests
bypass any test for lxc virtual
LXC managment improvments

- Add functions to the module
- Introduce a new state module to manage lxc containers via salt states
salt.modules.lxc: add ip & size to infos
salt.modules.lxc: fix lxcconf gen. and add extra infos to list
salt.modules.lxc: add dns servers managment
salt.states.lxc: pep8
Adding persistence support and load for Raet Road