bugfix: items will be saved in mysql databases also no icon is available
prevent error on png conversion
Switch from the shortcut.js to the jquery.hotkeys.js library.

The original shortcut.js library has trouble handling special keys.
For example, if a shortcut for 't' is defined, pressing F5 will
trigger it because the keycode for F5 is equal to the charcode for
't' (116).
Merge pull request #48 from Sigill/jquery.hotkeys

Switch from the shortcut.js to the jquery.hotkeys.js library.