Generalise the searchbar and tabs to support multiple controllers
The search facility should be accessible from all controllers
Fixes #248 - Generalise tab management and search facility
The search facility is now available from all controllers.
The search bar is only displayed if there is a partial
<controller_name>/_search_line.html.erb available.This partial also
describes and implements the possible search parameters for this controller
Active tab management is also improved
The appearence of the searchbar and other page elements has also been improved.