FMSLogo Code

Fix bug #2813364; SETPENCOLOR and other commands that input a color now throw recoverable bad input errors on more bad input.

This change also centralizes the code for converting a color input into a color for more consistent behavior (before, SETPIXEL and GIFSAVE used a different function and so did not accept names for colors).

This change it not a big benefit for users. Instead, it was done to make the test pass go more smoothly.

This commit was manufactured by cvs2svn to create tag 'VER-6-25-0'.

Add in the changes from 6.25.0.

Update the SELECTBOX tests now that the OK and Cancel buttons don't have accessor keys.

Updated based on a successful 6.25.0 test pass.

Include turtle.bmp in the release.

Fix a regression where zooming to a very small number (1e-20) would cause the WM_PAINT handler to coerce a large number into an integer, resulting in an unhandled floating point exception. My fix was to keep the numbers as floating point values until they had been clipped into the proper range before converting them back into ints.

Refactoring: replace code that called numeric_arg() followed by numeric_arg_to_flonum() with a single call to float_arg(). This was done to make the code more readable, but the resulting code should also be a little smaller/faster.

Refactoring: rename pos_int_arg() to nonnegative_int_arg() to better reflect what it does.

Refactoring: remove some redundancy from float_arg().