installation: improvement of OS X installation

* Removes `sudo` command when installing bower, less ,
  clean-css, requirejs, uglify-js.

* Fixes some `note` elements.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>
deposit: doi syntax validator improvements

* Makes the DOI validator stop validation.

* NOTE the name of the validator was changed to DOISyntax validator
  because of convertion to a class.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
search: facets unicode error fix

Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>
messages: general refactoring, fixes and improvements

* General refactoring and improvements including methods cleanup,
  API additions, oauth fix in REST, docstrings fixes.

* Adds pagination to REST API.

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