updates
- created new sets of operators *ToGrid
  ZoneToGrid: create grids from zone with building count
  FootprintZoneToGrid: create grid from footprint and zone. if zone has building count > footprint count,
                       additional building count in zone is distributed out according to area
                       (leftover from total-footprint area)
- added test cases
- deprecated following operators
  GridWriter, GridFromRegionWriter, ExposureGeometryWriter, FootprintAggregator, ZoneGridMerger, ZoneFootprintMerger
  will delete in next commit along with their test cases

- minor updates to some ui elements using qt designer
- refactored all UI strings back to qt/ui/*_ui.py files. (auto generated from qt designer)

- created wizard to help populating the input data tab
- allow user to create blank project and save later.
- added "Save as" functionality

- adding modifier now restricted only to be same attribute as main
updates
- user now will specify output file name instead of folder when save MS leaves and export exposure
- allow editing zone names in mapping scheme widget
  NOTE: not complete, must be check for how zone is created to disallow delete/edit zone names
        that were created from gis file
- new features added to taxonomy classes
  - generate valid strings
  - signature of function to get codes for attribute with(out) given parent
- fixed bugs in data wizard
- fixed bugs in *ToGrid operator, grids not generated in right location
- fixed bug in appendbranch. must allow append without modifying weights, otherwise
  loading from library will generate error
- started to fix workflow of CompleteSurvey to grid
- use_sampling set to be off by default
- allow user to set ranges when creating new mapping scheme from scratch
  NOTE: ranges set for automatic aggregation from survey is re-used
- editing ui text