Made several changes: 
1)Added customized icons for res/drawable(mdpi,hdpi,xhdpi, and xxhdpi)
2)Changed color of text custom style
3)Added text validation for user input error on TodoActivity and
EditItemActivity:
	-user no longer able to save a blank to do item upon editing
	-Error message appears and gives specific error message.  
	-Error icon appears and alerts user to error
	-Error message disappears once user begins to type. This
functionality saves user from having to click away error message.(user
friendly)
Added customized icons, text validator for user input and customized font