Fix mount.active command on FreeBSD.

Uses `mount -p` on FreeBSD as neither of the `/proc/self` files
currently used to determine active mounts exist on FreeBSD systems.
Implemented XenAPI backend as a 'virt' __virtual__ module to handle the Xen hypervisor
Ensure mount options come before special and node.

Fixes calls to mount where an fstype is specified.
Add Xen DomU detection for FreeBSD.
do a deep copy of ret. Don't alter original
Remove old option to pass in pkg names
Use a deepcopy when assigning list_pkgs results to __context__

This fixes a problem that Dave found where a simple assignment caused
the data in the return dict to be linked to __context__['pkg.list_pkgs']
due to a shallow copy, and thus the call to pkg_resource.stringify was
modifying the data in __context__['pkg.list_pkgs']. Dave will be pushing
a commit later on that fixes this in win_pkg.py, this commit fixes it in
the rest.
Merge pull request #5173 from terminalmage/quickfix

Use a deepcopy when assigning list_pkgs results to __context__
remove unneeded quotes
Merge pull request #5174 from UtahDave/develop

Fix list_pkgs on Windows.
Make explicit context overwrite kwargs for templating, Fix #5161
Merge pull request #5175 from basepi/context5161

Make explicit context overwrite kwargs for templating, Fix #5161
Fix syntax error in jinja context examples

Bad indentation meant it would pass in the pieces of context as part of
the **kwargs, rather than as part of the context kwarg.
Merge pull request #5176 from basepi/jinjadocs

Fix syntax error in jinja context examples
smartos_imgadm : add a *basic* search option and an update function

* update_installed() (aka. imgadm update)

* avail(search=None) : outputs the last occurrence of 'string' from
'''imgadm avail'''
Merge pull request #5178 from virtua-network/imgadm_feature

smartos_imgadm : add a *basic* search option and an update function
Remove retcode arg from cmd._run, Fix #5112

Checked for external uses, there are none.  Really not sure what it was
gaining us in the first place, but it's been out of use since the fix
for #2640.
Removed useless commands and added Xen dom0 support for NetBSD
Merge pull request #5179 from basepi/retcode5112

Remove retcode arg from cmd._run, Fix #5112
Make pkg state work with Windows packages