Updates installation instructions for Alchemy v3.0 [ci skip]
Make the current_user configurable

Makes the function configurable that is called by `current_alchemy_user`
to get the current user. Set Alchemy.current_user_method to the name
of the custom function.
Merge pull request #449 from pascalj/current_user_configurable

Make the current_user configurable
Abort cap import:database task, if database is not mysql.
Do not require contents in params of Element#update.

This fixes an issue, where saving an empty element raises an error.
Do not import unnecessary sass mixins and css classes with menubar stylesheet.

Renames the .rounded-border sass extend into %rounded-border.
Ensures that all related models touch each other.
Fix bug in page#new overlay when clipboard contains a page.

Since the select_clipboard_tag helper has been removed, we use the rails select_tag helper instead.

Also added tab initialization when the ajax request for loading overlays succeeds.
Removes `render_cell_elements`helper. Closes #439
Fixes the permissions for author users. Closes #454

An author can visit not public pages, but can never see invisible pages in the navigation.
Ensures that the resource relation name is a symbol. Fixes #455
Removes the NonStupidDigestAssets install notes. It is now officially released \o/
Bump version to 3.0.0.beta2
More robust touch timestamps test for element and content.
README update.
Do not use String as element_id in acts_as_list scope_condition.

Fixes a bug with postgresql having a wrong element_id value for acts_as_list scope_condition, if element_id is nil.
Cleanup page validation specs.
Removes old todo file and adds contributing rules.
Ensures that the `tmp/cache/assets` folder gets shared between deployments.

This dramatically increases assets precompiling while deploying.
Removes link to guidelines from contributing notes.