Added stock tracking capabilities.
Added comments and removed commented out code.

Change-Id: I83e332b8932106e26fa510f2ee9c5529f89ba68c
Update test to reflect changes to interface

Change-Id: I994658287f6c42758b22f0af7cfe33eb00f5a566
Merge pull request #61 from mikeyman77/ui/chng_e

Added stock tracking capabilities