FMSLogo Code

Fix copy&paste errors in comments: gif -> bmp

Fix spelling error in comment: piecemiel -> piecemeal

Add support for DumpBitmapFile() for WX_PURE platforms for high bit depths.
The intention was to add enough support on GNU/Linux to be able to run drawing tests that call CHECKSCREEN.

Refactoring: Move the cleanup code in lpolyend to the branches where it's needed.

Fix a typo in a comment.

Cleanup: remove dead code from uppitch and rightroll
The code has been commented out since MSWLogo and was intended to prevent their use when defining a polygon.
At this point, there's too much of a compatibility risk of enable this code.
Also, the real requirement is that polygons be planar, which makes this check too strict, since you can use these and still have planar polygons.

Uppercase "Bug" for consistency

Fix bug #543; POLYSTART and POLYEND no longer show modal dialog boxes for errors
Instead, they throw "Invalid State" errors.

Add a comment to explain that the argument to atan2 are reversed.

Relabel the inputs of ELLIPSEARC2 to match the documentation.
This brought to light the apparent mislabelling of x as y and vice-versa that had confused me before. I'm confident in the naming of the inputs, but not as much in the naming of the local variables.

The good news is that, even if the variable names are incorrect, the procedure still passes all tests.