refactor base handler to not require Wakka class
adds model methods to help ShowHandler work around using Wakka class
refactors WikkaWebService to add dispatch methods and to expunge Wakka class from show handler
refactors ShowHandler to use Wakka class as little as possible
adds find_by_tag_and_time method to PageModel
fixes broken ShowHandler unit tests
removes obsolete WikkaBlob unit test
fix broken WebService unit test