Extracts renaming/creation of alchemy_roles column to own migration.

When upgrading an app to Alchemy 3.0 it comes with an alchemy_users table. So the first migration of this gem (creation of alchemy_users) will not run. But the existing roles column of the app has to be updated to alchemy_roles anyway. That's the reason why we moved that column changing part to a separate migration and check if we need to rename or add the alchemy_roles column.
Merge pull request #1 from robinboening/separate_alchemy_roles_migration

Extracts renaming/creation of alchemy_roles column to own migration.
Uses svg logo instead of png.
Moves login.scss from alchemy core.
Adds position to module definition.

This module now has the same position it has before we extracted it into its own gem.
Use the alchemy kaminari theme in users pagination.
Fixes Alchemy version
Fixes redirect after resetting password.
Changes hotkey syntax to keymaster compatible syntax.

Alchemy 3.0 uses keymaster.js as hotkey library.
Use `%rounded-border` sass extend from current Alchemy master.
Removes the non-stupid-digest-assets dependency from the Gemfile.

The gem was finally released with all our fixes, so we don't need to require it explicitly, Alchemy already does this for us.
Load the encryptable module if devise-encryptable gem is used.
Bumps version to 2.0.0.rc1
added i18n files for nl

copied files from the english version for a proof of concept
this works so we can now begin to translate the complete files
Signup screen layout fixes.
Use Alchemy 3.0 new locale module for handling the translation.
Merge remote branch 'upstream/master'
Use new Alchemy 3.0 dialogs. Closes #2
Merge remote branch 'upstream/master'
added dutch translations