+ support comparison with double in quantity number protocol
Spreadsheet: Added setitem and getitem methods
Bumped version to 0.15 and added a temporary new splash
+ include missing header file
Have cmake set doxygen to use dot if it's available.

Also a minor typos
Forgot to add this to the last commit...
+ Mesh trim loses some triangles
+ fixes #0001499: Mesh trim loses some triangles
Arch: General improvements

* Removed roundings in exported objects
* Added toggleIfcBrepFlag command to force export as BREP
* Prepared Arch objects for Materials and custom IFC attributes
* Supported latest developement version of IfcOpenShell
* Cleanup of IFC exporter
* Export of Arch Sites as IfcSite
* Export of Groups as IfcGroup
Can now temporarially disable auto constraints in Sketcher by pressing Ctr

Implementation is a bit messy - look at cleaning up the signal/slot
connections between ViewProviderSketch, TaskDlgEditSketch,
TaskSketcherGeneral, and TaskSketcherConstrains...

I think an additional fix would be to prevent the GUI from suggesting
a tangential constraint that's colinear with the center of the circle.
Started implementing cancel for snap to grid
Added shift to disable snap-to-grid

Still need to work on integrating the "Command" better,
so that the user can change the key used for disabling
snap to grid, or automatic constraints.
Work on Command construction for the new modifier keys

It appears that the DlgKeyboardImp and Command classes aren't
setup to handle single modifier keys eg Ctrl or Shift by
theirselves.  So, currently the new Sketcher modifier keys are
hard-coded until those classes can be updated.  Stay tuned!
Fixed dumb spelling errors...