Get runtime tests to pass in mono

This pull request includes the following updates:

1.)  Minor fixes to Assist tests that had line breaks.  Those tests are failing on Mono with OSX (and I assume any Linux).

2.)  Change to accomodate an apparent difference between Guid parsing in .Net and Mono.  .Net will throw if given a string that is not the proper length, but Mono seems to pre-fill zeroes like this:

````c#
var value = "12000000-0000-0000-0000-00000000001" 
var guid = new Guid(value)                        
guid.ToString()
// "12000000-0000-0000-0000-000000000001"
value.ToString()
// "12000000-0000-0000-0000-00000000001"

There is existing functionality in SpecFlow tests to add the zero to the end, so I had to make a change to persist that behavior in Mono.