pllab: Simple routine to write labels

pllab (xlabel, ylabel, tlabel);

Routine for writing simple labels. Use plmtex for more complex labels.

xlabel (const char *, input)

Label for horizontal axis.

ylabel (const char *, input)

Label for vertical axis.

tlabel (const char *, input)

Title of graph.

Redacted form: pllab(xlabel, ylabel, tlabel)

This function is used in examples 1,5,9,12,14-16,20-22,29.