Added functionality to support installArguments in packages.config

This Pull Requests add an additional attribute to the package.config named "installArguments".
This attribute basically does the same as you would provide the "installArguments" paramer
 to the "chocolatey install" command.

Originaly sent with https://github.com/chocolatey/chocolatey/pull/336#discussion_r6380358 but from the wrong branch.