FMSLogo Code

Change the background for BITMAPTURTLE.SMOKETEST to reach into the corners.

Cache a value instead of recomputing it.
This is less for performance than to make it clear that it's the same value being reused.

Replace "HDC TempMemDC" with a wxMemoryDC for better portability.

Avoid multiple calls to GetScreenHorizontalScrollPosition/GetScreenVerticalScrollPosition
gprof says that this takes a long time, but I don't know if that's trustworthy.
Even if not, calling those methods half as many times isn't bad.

Don't use a back buffer was used when drawing regular turtles.
This was a regression that was accidently introduced when adding a back buffer for all bitmapped turtles (instead of just sprites).
This regression caused a 200% slowdown in the squiral benchmark.

It doesn't make sense to use a back buffer when drawing normal turtles, as there is other logic to draw them directly to the screen as the turtle is moved, bypassing any back buffer.

Add missing header files to fix build breaks when compiling without a precompiled header.

Add benchmark results for FMSLogo 8.3.0

Update expected test results based on second 8.3.0 test pass (after fixing a test bug in dll.lgo)

Update results based on the 8.3.0 test pass

Fix a test bug that caused a crash (invalid memory read)
Also remove repeated test cases.