preliminary privlege escalation unification + pbrun

- become constants inherit existing sudo/su ones
- become command line options, marked sudo/su as deprecated and moved sudo/su passwords to runas group
- changed method signatures as privlege escalation is collapsed to become
- added tests for su and become, diabled su for lack of support in local.py
- updated playbook,play and task objects to become
- added become to runner
- added whoami test for become/sudo/su
- added home override dir for plugins
- removed useless method from ask pass
- forced become pass to always be string also uses to_bytes
- fixed fakerunner for tests
- corrected reference in synchronize action plugin
- added pfexec (needs testing)
- removed unused sudo/su in runner init
- removed deprecated info
- updated pe tests to allow to run under sudo and not need root
- normalized become options into a funciton to avoid duplication and inconsistencies
- pushed suppored list to connection classs property
- updated all connection plugins to latest 'become' pe

- includes fixes from feedback (including typos)
- added draft docs
- stub of become_exe, leaving for future v2 fixes

lib/ansible/runner/connection_plugins/libvirt_lxc.py

@@ -22,6 +22,7 @@ import os
 import subprocess
 from ansible import errors
 from ansible.callbacks import vvv
+import ansible.constants as C
 
 class Connection(object):
     ''' Local lxc based connections '''
@@ -50,6 +51,7 @@ class Connection(object):
         self.host = host
         # port is unused, since this is local
         self.port = port
+        self.become_methods_supported=C.BECOME_METHODS
 
     def connect(self, port=None):
         ''' connect to the lxc; nothing to do here '''
@@ -65,16 +67,16 @@ class Connection(object):
             local_cmd = '%s -q -c lxc:/// lxc-enter-namespace %s -- %s' % (self.cmd, self.lxc, cmd)
         return local_cmd
 
-    def exec_command(self, cmd, tmp_path, sudo_user, sudoable=False, executable='/bin/sh', in_data=None, su=None, su_user=None):
+    def exec_command(self, cmd, tmp_path, become_user, sudoable=False, executable='/bin/sh', in_data=None):
         ''' run a command on the chroot '''
 
-        if su or su_user:
-            raise errors.AnsibleError("Internal Error: this module does not support running commands via su")
+        if sudoable and self.runner.become and self.runner.become_method not in self.become_methods_supported:
+            raise errors.AnsibleError("Internal Error: this module does not support running commands via %s" % self.runner.become_method)
 
         if in_data:
             raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
 
-        # We enter lxc as root so sudo stuff can be ignored
+        # We ignore privelege escalation!
         local_cmd = self._generate_cmd(executable, cmd)
 
         vvv("EXEC %s" % (local_cmd), host=self.lxc)