Type "./math" from the shell prompt to run Mathomatic using m4 as a macro
pre-processor for allowing easy entry of functions.  The executable file
"math" is a shell script and is only known to work with GNU software.
Available macros for functions and constants are listed in the file
"functions.m4".  Using this, trigonometry functions (sin(x), cos(x), etc.)
are implemented as complex exponentials in Mathomatic.

Readline and shelling out don't work while using m4, and the "quit" and
"exit" commands have some delay.  You can use control-D to quit, instead.
Also, the read command currently doesn't use m4, so it can't process
functions.  The only way to read in files with functions is to type "./math
<filename" from the shell prompt.
