Added simple mode stuff - work in progress

- Added check for simple mode in settings if database exists
- Added simple mode view on main page
Master password opens database from main page in simple mode
Added show more info switch on main page for simple mode
Updated application settings

- Added switch for "Single database mode" on main page which in fact toggles simple mode.
- Clear clipboard is now saved as seconds in settings file. Thus if later the interval shall be changed that can be done easily by adjusting the value. Currently the value 0 means Clear clipboard is off and a value of 10 means clearing the clipboard after 10 seconds. This is now default.
Update banner is not shown when installing ownKeepass for the first time
Fixed inputmethodhints for verify password text field on Query password dialog
Implemented create new database on main page in simple mode
Updated application settings help page

- Added description for simple database loading and clear clipboard.
Updated readme and cahangelog page for beta release 1.0.17

- This closes #33