adds options for client certs to downloader class

Adds :client_cert to the env array and then passes it into the curl
options array
adds param for client certs

adds an option to the command parser for client certicates
adds client cert
adds client cert to default config
adds accessor for client_cert
passes client cert option from Vagrant file to box_add
Merge branch 'master' into client-certs
implemetn array arguments from #1569
check ENV for VAGRANT_NOCOLOR (equivalent of --no-color on cmdline)
Ansible: Improvements for 'extra_vars' argument

`extra_vars` argument can now:
- contains a hierarchical set of parameters (instead of flat Key-Value Pairs)
- alternatively refers to a configuration file (instead of embedded Hash)

See Ansible Documentation for version requirement details:
http://www.ansibleworks.com/docs/playbooks_variables.html#passing-variables-on-the-command-line
Allow owner & group to be supplied as an Integer and skip lookup
Restore correct pathing
.vimrc with vagrant tabstop settings

Signed-off-by: BlackEagle <ike.devolder@gmail.com>
compatibility with rubygems 2.x
Store the final `provision_enabled` value to env

Let other middleware actions to know if we are really going to run the
provisioners.
Add shortcut for setting the memory size for VirtualBox VM
core: Allow hooking before and after provisioners
core: Improve provisioner hooking by introducing a new builtin action for wrapping provisioner runs
core: Fix action name used for ProvisionerRun
core: Pass on the newly added box to the rest of the middleware stack