BibFormat: fix snippets for phrase queries

* Displays correctly snippets for phrase queries.
* Corrects highlighting of only whole words.
  (closes #1201)

Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
Merge branch 'maint-1.1'

* maint-1.1:
  BibFormat: fix snippets for phrase queries
solrutils: add documentation

* Adds Solr documentation to the BibIndex and BibRank Admin Guides
solrutils: better invalid character handling

* Removes invalid characters (closes #1197)

* Consolidates removal of control characters
  and invalid characters

* Adds unit tests for character removal
solrutils: removal of unused code

* Search results are directly retrieved by opening a Solr URL
solrutils: better collection filter generator

* Empty filter gets accepted by Solr
solrutils: fix for ranking result display

* Passes jrec and rg for id output format
BibRank: detect external word similarity ranker

* Detects if Invenio uses external word similarity ranker
solrutils: add search and ranking tests

* Adds unit and regression tests for search and ranking

* Amends existing BibRank and WebSearch unit tests to only test
  native word similarity ranker

* Merge note: amended kwalitee in the following files:
    modules/miscutil/lib/solrutils_unit_tests.py
    modules/miscutil/lib/solrutils_regression_tests.py

Tested-by: Tibor Simko <tibor.simko@cern.ch>