added utility module

implemented WebAPI
implemented Pool
implemented TestCase
implemented configuration for bricks

added config argument to Wall.__init__
added Wall.add_message_handler
added config and logger properties to Brick
implemented Dropbox search

implemented architecture for search handlers in wall.bricks.url
integrated search handlers in URL UI
added README for URL brick
updated test command in README
Merge pull request #47 from NoyaInRain/dropbox

Implements Dropbox search