Add autoreject_file support to minion authentication

This commit adds support for a file similar to autosign_file, which can
be used to automatically reject minions which match the expressions
inside it.
prepend root_dir to autoreject_file
Add autoreject_file to master config template
Add autoreject_file to master config file documentation

Included a versionadded directive to note when this was added, to reduce
confusion.
First attempt at abstracting ZeroMQ communication.
lint fixes
check for config.get
Add doc for yaml_utf8
Warning does not reflect the correct deprecation path, removing for now
Add support for testign against python 2.6
Merge pull request #9241 from techhat/atfork

Re-init Crypto.Random.atfork() to prevent multiprocessing bugs
Apply yaml_utf8 to test config
Re-init Crypto.Random.atfork() to prevent multiprocessing bugs
fix syntax error
Quiet Pylint
Changed underlying error message to be more concise
Take into account lower PyCrypto versions (<2.1)
Update docs to reflect pycrypto dependency
Re-add the pylint disable comment
Merge pull request #9243 from techhat/atfork

Update docs to reflect pycrypto dependency