added separate class for item row object (to encapsulate the code for creating each row)
re-added changes from 79cad6b3b1
added methods to make plus and minus buttons work
Merge branch 'amartin' of https://github.com/asmartin/foodtracker into amartin

Conflicts:
	src/com/example/first_app/ItemView.java
	src/com/example/first_app/MainActivity.java