I was too lazy to put in all known elements, but I made it
easy to add the missing.

Every time ipc is called it reads a file called elemente which 
contains for every element its chemical symbol its isotopes and
their probabilities.

The entries in the file have the following form:

<chemical symbol>
<mass 1st isotope> <probability of 1st isotope>
 	.			.
	.			.
	.			.
<mass last isotope > probability last isotpe>

If an element you need is not present in this file you can
add this element by adding an entry like shown above. Next time
you start ipc the parser will recognize the added element with the
<chemical symbol> you put in.

The chemical symbol must start with an upper case letter.
It is highly recommended to give the isotopes in ascending order.