Dynamic lat lng title names

Added the ability to pass latitudeTitle & longitudeTitle in the options.  This allows for the use of firstLineTitles without forcing the csv to use lat lng field names.  
Often times users won’t have control over the incoming field names from automated processes and should be able to override the lat lng field names through the options while still being able to use firstLineTitles. This allows for greater flexibility.

latitudeTitle & longitudeTitle both default to their previously hardcoded values so these changes won't break existing code.