Fixed: Some templates used changeTab in a way that was not compatible with the new options to discard changes on changeTab

Implemented:  FS#2388 - Optional confirm window on changing tabs

- Random password length: by default, generated passwords will have a length between 10 and 15 characters (instead of a fixed length of 10 characters).

- Added "Generate Password" links to forms of the sites module.

- Added "actions" framework in server to replace the functions provided by the core modules
- Moved system update function from remoteactins core module to software update plugin.

FS#586 and commit 1082.

It is now possible to redirect to a different url as result of the loadContent AJAX function

- Fixed bug with maildir creation in mail plugin.