Ensure that all index views and controllers are consistent

Ensures that all controllers use @search in the index method
Ensure that all index views use pagination

removing show action in places it doesn't make sense, and minor visual changes

fixes #201 - Remove activescaffold from the domains page

Added some more text to the settings menu, removed some fields which are not yet required.

added domain and common specific parameters.
this adds a similar functionality to extlookup.
the order in which parameters are processed is:
common => domain => hostgroup => host
where the latest occurrence of a parameter takes priority.

removed helper from all controllers by default, this can conflict with AS
when having multiple fields with the same name.. e.g. name

added some basic nested views

fixed an issue with wrong contoller names which lead to broken links, redid some model relationships (hopefuly simplified - hence removed the nested_has_many_through plugin