Added demo fragment at clicking edit button

In ManageUsers onClick event of Edit button
creates a demo fragment. Position of fragment
has to not been managed yet.
In ManageUser fragment is displayed below buttons

The demo fragment was earlier displayed at top
of activity.
Now it is positioned below the edit and delete buttons
Demo fragment replaced by username/password fields

	Username and Password fields added to fragment
	Fragment is displayed at onClick event of Edit button
	Changed text size of Spinner
Few changes in UserDatabase layout

	Added text for userlist
	Spinner alignment changes
Fetching username and password to Editing fragment

	* Created a class UserStructure to access
	  username and password. It implements getters
	  and setters.
	* Activity UserDatabase gets username and
	  password from database and sends them to
	  fragment FragmentEdit
Display username and password in edit fields

The text set to be displayed is not showing
Username and password showing in edit boxes

onClick event of edit button in activity edit
shows selected username and password in their
respective edit boxes