testutils: enrich InvenioWebTestCase class

* Enriches helper functions for web tests in order
  to be able to find elements also by id:
   - element_value_test(element_name="", element_id="")
   - choose_selectbox_option_by_label(selectbox_name="", selectbox_id="")
   - choose_selectbox_option_by_index(selectbox_name="", selectbox_id="")
   - choose_selectbox_option_by_value(selectbox_name="", selectbox_id="")
   - fill_textbox(textbox_name="", textbox_id="")
* Enriches the helper function element_value_test()
  in order to be able to get the value of a given element
  that is not a textarea or a textbox.
* Adds new helper function:
   - find_elements_by_class_name_with_timeout()
* Amends web tests as needed because of this enrichment.
  (addresses #798)
BibEdit: adapt web tests to the new framework

* Adapts BibEdit web tests to the new web test framework.
  (closes #798)
intbitset: add support for pickle protocol

* intbitset can now be pickled and unpickled using either
  pickle or cPickle module.
BibFormat: add ScienceWise icon for CDS records

* ScienceWise.info can now explicitly refers to native CDS records,
  regardless if they have an arXiv reportnumber.  A special linking
  is indeed needed, and it is here implemented.
WebSubmit: new Link_Records functions

* New function to create a link between a record being
  submitted and an already existing one.
demo site: fix SQL insertion error

* Fixes SQL insertion trouble introduced in the previous commit
  5ce0305fc7442dbd017b302fefcf07d2a93cc1c0.
BibSched: facility to start tasks at fixed time

* Adds new facility that permits to start certain tasks (such as
  oaiharvest) at fixed time, regardless of the status of the queue.
  (closes #794)
BibSched: add support for task sequences

* Adds support for task sequences via sequence id.
  (closes #796)
I18N: complete Catalan and Spanish translations
WebComment: better tear down after web tests

* Improves the way to delete inserted test comments and reviews.
BibEdit: use WebDriverWait to wait for JS refresh

* Enriches the helper function "find_element_by_id_with_timeout()"
  to wait for an element and its correct content which is
  changed/refreshed using JavaScript.

* Amends BibEdit web tests with the new improvement.
WebStyle: better service failure message
WebComment: improve markup

* Ensure that 'name' attribute is valid (i.e. does not
  start with number).

* Added 'id' attribute in addition to 'name'.

* Fixed URL redirection after a comment is reported or
  voted.
WebSearch: fix nearest search terms URLs

* Fixes broken URLs for nearest search terms when searching inside
  indexes with a query containing uppercase letters and added
  regression tests. (closes #633)

* Fix broken URLs for nearest search terms when searching using
  SPIRES syntax (ex:find a foobarxyz) and added regression tests.
  (closes #724, #741)
WebSearch: fix field matching
Websearch: fix display in HVP output format

* Fixes the position of the bottom navigation links in the HTML
  video portfolio format.
intbitset: fix Python-2.4 compatibility

* In commit a06a52b7cd603fce327a1d915639c7b5ebd7a650 pickle
  interface has been added to intbitset. However that implementation
  was using a feature not available in Python-2.4. This is now
  fixed.
BibUpload: fix Python-2.4 compatibility
WebSearch: fix language name in translation boxes

* Removes "(def)" signature after language name in the translation boxes
  in order to avoid default/definition confusion, in the WebSearch Admin
  UI but also in BibRank and BibIndex Admin UIs.  (closes #901)
WebStyle: serve 503 HTTP code when in maintenance

* If the site is in the maintenance mode, i.e. if
  CFG_ACCESS_CONTROL_LEVEL_SITE > 1, then always serve a 503
  HTTP error code by default, so that crawlers don't index
  the site. (closes #805)