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

test/integration/roles/test_sudo/tasks/main.yml

@@ -1,9 +1,20 @@
 - include_vars: default.yml
 
 - name: Create test user
+  sudo: true
   user:
     name: "{{ sudo_test_user }}"
 
+- name: test becoming user
+  shell: whoami
+  sudo: True
+  sudo_user: "{{ sudo_test_user }}"
+  register: results
+
+- assert:
+    that:
+      - "results.stdout == '{{ sudo_test_user }}'"
+
 - name: tilde expansion honors sudo in file
   sudo: True
   sudo_user: "{{ sudo_test_user }}"
@@ -56,6 +67,7 @@
       - "results.stat.path|dirname|basename == '{{ sudo_test_user }}'"
 
 - name: Remove test user and their home dir
+  sudo: true
   user:
     name: "{{ sudo_test_user }}"
     state: "absent"