Version 0.1.5

New features:

• The "Merge cell seg files" addin now supports searching sub-directories
  for target files.
• The "Consolidate and summarize" addin remembers the last directory
  for subsequent selections.
• More informative error message if consolidation fails due to mis-matched
  data files.

Bug fix:

• compute_density works with "square microns" spelled as inForm does.