collect: addition of filter for Blueprints

* Upgrades to Flask-Collect>=1.1.1. (closes #2353)

* Adds DeprecationWarning to Invenio link storage.

* Updates .travis.yml.

* Updates documentation.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
sqlalchemy: update version requirements

* Updated minimum and maximum version requirements for SQLAlchemy and
  SQLAlchemy-Utils.  (closes #1776)

* Fix compatibility problems with invenio.

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>