Improvements to search to prepare for showing highlighting.

 - SearchDescription has been renamed SearchHit
 - SolrQueryParser now parses highlighting information and
   makes this available to individual docs
 - The various controllers and views which receive search results
   now include with their context the complete search hit in addition
   to the corresponding item from the database. This will clear the way
   for using search context such as highlighting in result display.
Refactor query builder, dispatcher, parser to allow injecting different impls.
Rename URL validation function
Add search phrases to search hit context
Experimental search highlighting
Beginnings of support for external doc links to sources, via URL patterns
Non-functional cleanup
Refactorings in the pursuit of better per-type DB customisation.

 - The manual form of 'get' now requires a RestResource[T] instead of
   an entity type, 'cos that includes the defaultParams
 - Some magic to get dynamic Resource types for Accessor and AnyModel
 - URLs that have a type in the path now path bind directly to EntityType
   for less boilerplate.
More hacking away at item linking, added logo url for repos.
Rearrange list templates to account for possible search hit handling
Split out headers and other general styling tweaks
Ensure first comment/annotation always shows up
Attempt to simplify portal templates
More experiments with search highlighting
Fix boost so they're not effectively negative (whoops)
More work on highlighting, still somewhat troublesome
Improvements to header and css
Tiny css/routing tweaks
More css tweaks (fixed header bar) and small less cleanup.
Merge search highlighting and portal cosmetic changes.