Clean up extra comments in data_clean_merge.r
Remove blank rows to make it easier to work with
Add checks of matching stage names

All good except Sandblian and Dapingian but these are OK because they
match by time.
Critical bug fix: add na.rm = TRUE to means of proxies
Add back in OA to RMA
Remove a bunch of trailing white space (that's all)
Re-knit the document