plsesc: Set the escape character for text strings

Set the escape character for text strings. From C (in contrast to fortran, see plsescfortran) you pass esc as a character. Only selected characters are allowed to prevent the user from shooting himself in the foot (For example, a "\" isn't allowed since it conflicts with C's use of backslash as a character escape). Here are the allowed escape characters and their corresponding decimal ASCII values:

• "!", ASCII 33

• "#", ASCII 35

• "$", ASCII 36

• "%", ASCII 37

• "&", ASCII 38

• "*", ASCII 42

• "@", ASCII 64

• "^", ASCII 94

• "~", ASCII 126

esc (char, input) Escape character.