Introduces a Jinja2 template system for catalog
Progress for metadata support and testing
First iteration of changes to metadata mappings
First working iteration of the new metadata support

- Updated PyDAP to accept data product ids instead of dataset ids.
  - This is in preparation for supporting site data products and general
    system growth.
- Created a better metadata system and a cleaner way to interface with
  the XML document(s)
- Updated the test_pydap
- Included utility test for future development
Adds stubs for data product management methods