Merge pull request #85 from camilotorresf/fixes

Case insensitive profile (and email)
Admin users database sort and paginate

In the admin, the users database page now allows sort clicking on the table header.
Also supports pagination.
Admin: adds a tab for data loaders

In the search for users and in the all users in the admin, a new tab for Data Loaders is added with sort and pagination.
Refactor code

Use a mixin for fixing the date creation column in users search and dataloaders search results.