Fixed inconsistent versions in InChI download script (1.04) and documentation (1.03)

The download script was updated some time (perhaps a year ago) to download the then "latest" InChI stable software version (1.04).  This is the version which is recommended to use by IUPAC.  

However the documentation and some comments in the script still pointed to the old version 1.03.  Also the comments in the script were incorrect and have now been fixed.

Change tested on Ubuntu Linux 12.04.