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/funcd.py

@@ -53,16 +53,14 @@ class Connection(object):
         self.client = fc.Client(self.host)
         return self
 
-    def exec_command(self, cmd, tmp_path, sudo_user=None, sudoable=False,
-                     executable='/bin/sh', in_data=None, su=None, su_user=None):
+    def exec_command(self, cmd, tmp_path, become_user=None, sudoable=False,
+                     executable='/bin/sh', in_data=None):
         ''' run a command on the remote minion '''
 
-        if su or su_user:
-            raise errors.AnsibleError("Internal Error: this module does not support running commands via su")
-
         if in_data:
             raise errors.AnsibleError("Internal Error: this module does not support optimized module pipelining")
 
+        # totally ignores privlege escalation
         vvv("EXEC %s" % (cmd), host=self.host)
         p = self.client.command.run(cmd)[self.host]
         return (p[0], '', p[1], p[2])