updates
- added popgrid to zone workflow, also added test case for popgrid
- removed exception handling from statistic.add. caller must catch exception
- if mod_input table value is not valid, allow user to edit using standard input text box
  this allows fixing wrong values
- ms_level_table now allows setting specific cell to be editable
- updated ms_library to latest taxonomy
- wdg_ms, vertical labels now shows selected tab as black, not selected as gray
- open file now remembers last opened directory

fixed
- changed usage of int as key vs. raw object in shapefile export

generic
- changed extension of project file to .sidd
- updated ms.db (PAGER mapping scheme library)