Add get_selections() and set_selections() for dpkg.

This module will enable to freeze a package at a certain version, with the "hold" state.
Add TODO, amend later... FIXME.
possible fix for https://github.com/saltstack/salt/issues/5567
possible fix for https://github.com/saltstack/salt/issues/5567
Adds --show-timeout to force the display of unresponsive minions
Removes debugging and badly merged code
Add salt.utils.master with class MasterPillarUtil. Change salt.runners.cache to use salt.utils.master.MasterPillarUtil
Remove unnecessary variables.

Somewhere along the way salt's setup changed and some variable were left around. Let's remove them.
Make pylint happy, global variables are all uppercased.
Allow salt's paths to be configurable at build time.
supporting tomcat6
less copy/paste
Merge my dpkg-selections branch with develop.

Resolved conflicts in modules/apt.py.
Fix merge mistake.

urllib2 and json is part of standard Python.
Use yaml.safe_load()
Add another TODO
Use code-block

As per @terminalmage suggestion.
Fix tracebacks when prefix not specified.

This fixes #6886 by accounting for instances where the prefix is not
specified, catching the KeyError exceptions.
Double to single quotes.
Minor formatting updates.