cipher module for 1.3.5

[Sergi Blanch i Torné]

Hi,

Following the (unlisted) comments, the first modification in the ecc module is 
here. That change only is: write more comments in the code. Now, before all 
functions you have a little explanation of the objective of it code. I think 
now it is easy to understand the procedure, and is less necessary to read the 
documentation.

The 'ecc.c' now is separately accessible, also the diff (and 'src') are 
updated.

Thanks for you time.
-- 
Sergi