Prevent access violation in motioner's preview window rendering

Mesh::decalDraw() have not considered the case glClientActiveTextureARB
is not loaded.  Modern GPUs should have it, but motioner project
intentionally skipped loading the function pointer via wglGetProcAddress().

Note that motioner project won't immediately crash by the error since
access violation exception is handled.  The end result looks like
the preview window show nothing after loading some model.
surface: Delete obsolete motions for Apache

These motions tilt rotor axis, but in reality only rotor blade pitches are
controlled, so these motions no longer applied.
motioner: Add a checkbox to toggle wireframe rendering for preview
Squashed 'sqscripter/' content from commit ae07f47

git-subtree-dir: sqscripter
git-subtree-split: ae07f47a16d921830b4ff4cc90486c2c2af954b9
Merge commit '591262d93d65d3f40b8fc5d840e3637bb9a60fe9' as 'sqscripter'
Adapt to sqscripter project (modified SciLexer.DLL)
Adapt to Squirrel syntax coloring in SqScripter
Show compile errors in Squirrel scripts to SqScripter window
Show Squirrel runtime errors in SqScripter window

Now it can show source file and position where an error has occurred,
which helps debugging greatly.
Collect common codes between DrawTextureSphere and DrawTextureSpheroid
Move SSD files from the root directory to data subdir

Because the root directory is better be clear.
Rename README to README.md for better formatting for Github
Add some screenshot images for README.md