Initial refactor of the search app to better support related fields lookups, trying to fix issue #20 in the application side
Update documents app to use the new SearchModel class
Simplify code and variable names
Refactor advanced searching
Store instances of SearchModel by their full_name in the class registry
Improve a bit the way recent searches are saved
Update the RecentSearch model to work with the new SearchModel class
Get the document.Document SearchModel instance in a more elegant way