installation: Python 2.6 on Travis CI

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
Reviewed-by: Jiří Kunčar <jiri.kuncar@cern.ch>
installation: Flask-Collect to use 0.2.3-dev

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
Reviewed-by: Jiří Kunčar <jiri.kuncar@cern.ch>
access: using unittest2 in Python 2.6

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
Reviewed-by: Jiří Kunčar <jiri.kuncar@cern.ch>
workflows: Python 2.6 compatibility

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
Reviewed-by: Jiří Kunčar <jiri.kuncar@cern.ch>
docs: new documentation structure

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
base: wrapper doctest addition

* Adds doctests for `invenio.base.wrappers` that can be executed from
  source code folder: `python -m doctest -v invenio/base/wrappers.py`

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
oauth2server: fix for default redirect uri

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
jsonalchemy: memory engine search method addition

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
restful: `require_header` value checker addition

* Decorator accepts callable to test header value.

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
access: jsonalchemy acl extension

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
documents: acl extension usage
jsonalchemy: extension parser temporary fix

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>