Add multiple process option to c++ filetest template

Using Template options (#96), if the filetest template has the option RunMultipleProcesses set to true, then the c++ filetest template will run each test case in a different process. This way globals will always be in the original state. Runtime errors can also be caught.

Drawbacks:
* Must reread all the sample file for each test case.
* Not sure if it works in Microsoft's c++ compiler (does system() work there?)
* Can we really expect the program to have permissions to run a different process?

Comments:
* Should this behavior be the default?
* Config file uses lowercase (Maybe camel) fields.  Template starts with Upper case. Which is preferable to use for template option names?

You know, this was started after issue #90 .