[WP3] FITSIO download & installation instructions

[D.R. Boxhoorn]

Dear all,

Alfredo has been so kind to add download and installation instructions for
FITSIO in opipe/README, section "3. LDAC/Sextractor/SWARP/CosmicFITS/CFITSIO".

Please install it at your site if you haven't already done so, and let me
know when you have.

This is important because the latest `ingest.py' script is using FITSIO
compression when data are ingested. After everyone has installed FITSIO
I can move the AWBASE tag.

Good luck,

                                                   Danny