Added -Job parameter

-Job takes a path to an XML config file to define a path to a global variables file, and plugins.

Basic format of the config is as follows:
<vCheck>
   <globalVariables>GlobalVariables.ps1</globalVariables>
   <plugins path="plergins">
      <plugin>00 Connection Plugin for vCenter.ps1</plugin>
      <plugin>03 Datastore Information.ps1</plugin>    
      <plugin>99 VeryLastPlugin Used to Disconnect.ps1</plugin>
   </plugins>
</vCheck>