Mystran encoding issue

[SteveDoyle2]

Unnecessarily writing a special character leading to more difficult parsing for users. Not everyone knows how to work with unicode, even if some people do.

If the input file has it, fine, but it should not be added by Mystran for a grid point forces table.

I propose changing the U double dot to an A (for acceleration). The capital letter is nice because it won't clash with the a-set, Ua. Note that Ug is seen in the picture. Based on context of inertial force (F=ma), it should be pretty obvious.

I'm calling this documentation, but it's file documentation.