Adding typemap to convert String to const openstudio::path&

This should be completely backwards compatible, I don't think we should provide an out typemap so openstudio::path values are returned as String.  I also don't know if we want to advertise this as the preferred way to write code, I would continue recommending using OpenStudio::Path if possible.

@lefticus can you take a look at the the typemap?  Should we also provide a type map for "openstudio::path" and "const openstudio::path"?

@nllong this is a present for you
Changing STR2CSTR to StringValuePtr for compatibility with Ruby 2.0
Adding failing test, need to fix this before merging
One more test to check that both generated overloads work
Applying suggesting from William Fulton on SWIG user mailing list
Finally working!
Add python bindings for string path
Remove path python binding input choice

Removes ‘None’ as a valid input choice for path typemap in Python
bindings. This is more consistent with the Ruby bindings now.
Merge pull request #759 from ORNL-BTRIC/ImplicitPath

Add python bindings for string input for Path
Merge pull request #735 from NREL/ImplicitPath

Adding typemap to convert String to const openstudio::path&