Added credit card validation to the restaurant app.
fixed crash on user pay bill
Fixed empty string case
Fixed input type for layout
Merge pull request #291 from glee23/master

Added credit card validation to the restaurant app.
Merge branch 'master' of https://github.com/mhotan/DineOn into phase_4_dev

Conflicts:
	DineOnRestaurantApplication/res/values/strings.xml