Websearch: fix results when applying search limits

* Fixes prs_apply_search_limits so that the results_final dictionary is
  updated, rather than re-defined locally.

(closes #1750)

Signed-off-by: Nikolaos Kasioumis <nikolaos.kasioumis@cern.ch>
Co-Authored-By: Ludmila Marian <ludmila.marian@gmail.com>
installation: pip requirements version update

* Updates python-twitter in requirements.txt to the latest version
  (2.0) that supports Twitter 1.1 API.

Signed-off-by: Sebastian Witowski <sebastian.witowski@cern.ch>
WebSearch: fix for snippet highlighting

* Highlights terms that are only searched in fulltext.

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
WebNews: New module to display and manage news

* The WebNews module that will be responsible for presenting the site's news
  to the users and keeping a history of them. (addresses #1288)

* This first release includes the tooltip functionality and the database
  structure.
WebLinkback: faster email notification

 * Improves database layer to send email notification faster

 * Extends regression tests for this improvement

 * Applies minor clean-up
WebLinkback: faster deletion of linkbacks on blacklist

 * Avoids redundant creations of blacklist
SolrUtils: reliable regression test suite

* Makes test suite independent from PDF extraction process.
  (closes #1590)

* Simplifies test suite

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Merge pull request #28 from pglauner/master-solr-regression-tests

SolrUtils: reliable regression test suite
WebSearch: new parsing of unbalanced phrase queries

* Removes unbalanced double quotation marks.

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Merge pull request #29 from pglauner/master-search-units-phrase

WebSearch: new parsing of unbalanced phrase queries
WebSearch: new fulltext by default search

 * Adds checkbox to search terms also in to fulltext to the add
   to search interface.

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
BibRank: Solr: better ranking for fulltext by default

 * Ranks fulltext and metadata properly

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Solrutils: more accurate ranking scores

 * Ceils ranking scores to avoid anomalies

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Merge pull request #30 from pglauner/master-fulltext-by-default

See last comment in <http://github.com/CERNDocumentServer/cds-ops/pull/30>
regarding kwargs.
BibRecord: new MARC code filter

* Filters a record based on MARC code

* Supports wildcards in identifiers and subfield code

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
BibFormat: new 'xmf' format

* Supports filtering per MARC tag, identifier and subfield

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Merge pull request #31 from pglauner/master-xm-fielded

Master xm fielded
Upgrades: safer new bibdocfile model upgrade

* Uses the get() method instead of __getitem__() defaulting the return
  value to an empty dictionary in case of missing keys in more_info.
WebSearch: fix number of printed records

* Fixes the number of records printed when a ranking methond is
  used.

Co-authored-by: Nikolaos Kasioumis <nikolaos.kasioumis@cern.ch>
Signed-off-by: Ludmila Marian <ludmila.marian@gmail.com>
Merge pull request #55 from ludmilamarian/master_websearch_fix_sliceing

Master websearch fix sliceing