Language construct now uses faceting

When searching 'all projects', it also has language constructs
filters

A selected language construct filter is now discarded when the query
changes (it was easy to forget to deselect it and a new query mostly
doesn't target the same language construct)

Added Misc container at manage page for deleting orphan repos and
construct matches (latter not needed when using webdsl rev >= 5668)

Impl: Language constructs are now loaded dynamically with hit count,
similar to the file extension and file location facets. It uses a
different searcher for retrieval of facets
Each language construct match is now indexed using 2 tokens instead
of 1. One is used by the EntrySearcher, the other to perform faceting
using a ConstructMatchSearcher
Merge branch 'master' of https://github.com/webdsl/reposearch

Conflicts:
	language-construct/language-construct-data.app