Fix slowdown in collection

InfoBlock elements were generally defined in modules and as modules were
loaded at collection time, the collapsing of any InfoBlock elements
invoked an ssh and db check for the version. The .locate() is now
deferred to when the _box_locator is actually used within the code.
Merge pull request #737 from psav/fix_collection

Fix slowdown in collection
Coverage of advanced search box in Hosts

Adds a new web_ui module which can operate the advanced search box.
Adds tests testing the advanced search box in Hosts section.