v1.0
   Initial Release.

v1.0.1:
   Compile with GTK versions 1.0.x.

v1.0.2:
   Added undo.  Up to 10 commands can be undone. 
   Trap the Ctrl-c keypress and quit.

v1.0.3:
   Map the ^ key to the x^y function.

v1.0.4
   Handle keys in number pad correctly.
   Fix memory leak in asin and atan of complex numbers.
   Fix malloc/ free errors introduced with the undo feature.

v1.1.0
   Add hex, dec, oct, and bin commands.
   Add rip command.
   Command line args to set font and window size.
   Fix possible memory corruption bug when displaying matrices.

v1.1.1
   Force keyboard entry to be interpreted as a command when
      prefixed with a single or double quote.