Disabling plugins in depends-order

This commit disables/unloads plugins in their depends-order. So far, plugins were disabled in random order.
Example: _**A** depends on **B**_
**A** uses a MySQL connection which is handled by **B**. If **B** would be disabled first and **A** uses the MySQL connection in their onDisable() it would generate an exception.

This commit fixes this problem by checking the dependencies and disabling the plugins in logical order.
Actually, they were disabled in backwards order, not random.
Just change this line to reverse iterate