- Responsive fixes

- Included new icons and buttons
- Layout scaling improved (up to 1260px width)

- Select2 combobox

- Added HHVM to "Default PHP Handler" field (server configuration).
- Fixed "Unable to load the server configuration from database." error when running server.sh.
- Fixed Javascript (accordions weren't working anymore, directive snippets and other placeholders couldn't be added anymore).

- autoselect password if you use "Generate Password" function (saves a click if you want to copy the password).

 - javascript hooks prepared (onAfterContentLoad is first available hook)
 - new abstract class for GET and POST requests
 - new js.d directory that is included into main template

- New feature: you can now add directive snippets for Apache, nginx, and PHP under System > Directive Snippets. These snippets are then available on the Options tab of a web site where they can be easily added to the respective textarea by simply clicking the name of the directive snippet.

Fixed: password match function blocked tabs incorrectly
Fixed: set focus on username input field threw an error if this field did not exist on a page

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).