Python 3: there's no iteritems()

Make ansible.vars.unsafe_proxy Python 3 friendly

Instead of str and unicode we have to deal with bytes and str.

Fixes ImportError: No module named '__builtin__' on Python 3.

AnsibleModules.log() fix for python3

Also add unittests for AnsibleModules.log()

Fixes #12586

* corrupt/invalid file causes tracebacks
* incorrect initialization of display/_display in BaseCacheModule class
* tweaking the way errors in get() on jsonfile caches work, to raise
  a proper AnsibleError in that situation so the playbook/task is stopped

Fixes #12708

Fixes #12711

Added an option to use the private network IP address for DigitalOcean dynamic inventory 

Removed deletion of salt by 'password' lookup

added methods for retrieving vapp and vm

Merge branch 'serial_should_be_string' of https://github.com/klshxsh/ansible into klshxsh-serial_should_be_string

Note that this allows both integers (e.g. 3) and percentages (e.g. "30%")
Also changed default back to 0 rather than '0'

Adding the inventory_file var back

Update docs (playbooks_loops.rst, playbooks_filters.rst)

Installation update for people using Fishshell

Update synchronize module plugin to work on OS X

Update lookups doc with shelvefile example

The serial keyword can be specified as a percentage, e.g '30%' or a number e.g. '3'; therefore it needs to be a string to allow both types

Add Python 3.5 to tox.ini and Travis