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/action_plugins/fetch.py

@@ -78,7 +78,7 @@ class ActionModule(object):
 
         # use slurp if sudo and permissions are lacking
         remote_data = None
-        if remote_checksum in ('1', '2') or self.runner.sudo:
+        if remote_checksum in ('1', '2') or self.runner.become:
             slurpres = self.runner._execute_module(conn, tmp, 'slurp', 'src=%s' % source, inject=inject)
             if slurpres.is_successful():
                 if slurpres.result['encoding'] == 'base64':