Added initial  model, view, url and tests for marker symbology.

Created test for the symbology url and model __str__ method. Created the model  with a manytomany relationship to marker id in the Marker model. Created a list view and set up the url for the symbology.  Added symbology data to the inital_data fixture file.
Merge pull request #5 from jzmiller1/symbology_fb

Added initial  model, view, url and tests for marker symbology.