Add a changelog entry about changes in Array helper's element() and elements()
config->item() now returns NULL instead of FALSE when the required item doesn't exist.

Uniformization with other functions. This also brings the ability to properly use booleans in configuration.
Adjustments to the previous commit
Uniformize slash_item() with item()
Fix #2558
Fix #2560
Form helper: refactor form_open() and _attributes_to_string()
More logical order
Merge pull request #2565 from vlakoff/develop

Form helper: refactor form_open() and _attributes_to_string()
Merge pull request #2554 from vlakoff/develop-3

config->item() now returns NULL instead of FALSE when the required item doesn't exist.
Form helper _attributes_to_string() micro-optimization

As $attributes should be most of the times an array, let's save an is_string() call.
Polishing Form helper