Adds a search view and a test for it
Changed display of some boolean fields in detail template
Adds a list of received trade requests on user's index page
Adds a preview view for one's own listing
Several additions:
	* A send_trade_request view.
	* The detail view will display if the viewed listing has sent
	a trade request to the viewing listing, or vice versa
	* Changed template inheritance so that any messages sent
	via Django's built-in messaging will be displayed on any page
Adds ability to perform search function with empty text field
Adds a public search form to the start page.

Former start page for logged in users is moved to /dashboard/
Adds new user model to admin site
Updated tests to use correct url for search
Replaces explicit urls in test files with the reverse function
Adds a change_published_state Listing model function and view

Also adds a publish/unpublish button for listings to user's index page
Removed an incorrect line break in index template
Changes send_trade_request view to require a POST request
Adds an assertion to the search test that an unpublished Listing
will not show up in a search result
Makes the test for the create_listing view more thorogh,
and also asserts that a created Listing will be published
Adds function for a user to delete a listing
Adds support for a base css file.

Note that the actual base css file is in another repo!
Moves common static files into the project path

They are no longer in a separate repo. Thank god! Ignore that line
in the last commit.
Adds a public detail view for listings
Adds a trade request detail view for receiving user,
and the ability for the receiving user to decline a trade request