Improved variable names

Change-Id: I4a694e28f33795ff05ee6e8a690868f5f9056545
Added comments

Change-Id: Id19ce8d9ec009713eaa66216aa9b1039267e7fd2
Add crude progress reporting

Change-Id: Iecfcf7d01d72679be97bc9bd06e77e9bb43cf864
Added cells and cell data to test

Change-Id: I7f2b0586e2cd900a1b0a816f38a45f87f43e04eb
Added tests for appending cell data

Change-Id: If196eff05c18043a9890b2f800e7a435416863f9