Rotated ELLIPSE flag

[stevencombs]

For feature completeness, as is available on the C128 in BASIC 7.0, BASIC 65 needs the ability to create a rotated ellipse. In 7.0, this was done with the CIRCLE command. Since BASIC 65 includes and ELLIPSE command, a new flag is suggested for rotation angle.

I ran into this limitation when trying to port a C128 BASIC program to the MEGA65.

[dansanderson]

Happy to have this feature request and to help get it added to BASIC 65. For the record, there is no documentation support for the idea that BASIC 10 would have included this. But an "angle" argument for ELLIPSE similar to C128's CIRCLE makes enough sense.

We may need to dig out the C128 ROM source to mimic their algorithm. I don't have that handy.