doc: Rename template.py->api_template.py. Walk for module names.
database: Move into package. Rename add()->add_many(). Rm url_encoding col.

Move database module into package. Seperate base tables from SQL
implementations.

Rename methods such as add() to add_many() in base table to avoid
confusion of parameters. Remove Mapping inheritance to emphasize it is
not a high performance container.

Changed table to have check_in() and check_out() methods to emphasize
their correct use.

Removed url_encoding column from the urls table. Expectation is that
URLs are percent-encoded by the author and Wpull has no gaurantee of
handling the encoding correctly.

Rewrote some of the queries so that URLStrings no longer has a cache of
row IDs.
Fix database modules import references and updated function names.
doc: Update API docs with new modules.
setup.py: Update packages to incldue wpull.database