installation: dependency links renovation

* Prepares `setup.py` for Invenio v2.0 release for pip<1.6.
  (addresses #1797)

* NOTE use `pip install --process-dependency-links -e .`

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
formatter: fix Bibfmt model import

* Fixes broken import of `Bibfmt` model.  (closes #1781)

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
legacy: fix javascript on /record/edit

* Addresses issue with record editor not loading record data.
  (closes #2143) (PR #2178)

Co-authored-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Petr Broz <petr.broz@gmail.com>
sqlalchemy: refactoring and addition of Encrypted Type

* Addition of package `types` inside ext.sqlalchemy package.

* Refactoring the current types by removing the `types.py` file
  and adding each type to separate file.

* Addition of a type named `Encrypted` that will be used for
  encrypting and decrypting access_tokens.

* Refactors the class by adding private functions for encryption
  and decryption.

* Adds docstrings.

* Renames methods names starting with double underscore to names
  with one underscore.

* Adds the `Encrypted` class to the types init file.

* Addition of pycrypto(version 2.6.1) to `setup.py`.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>