Updates to azgcorr (and azexhdf)

1. change to the arsf user
2. copy the release file to ~arsf/usr/arsf_releases/relXXX.tar.gz (rename to add .tar.gz)
3. uncompress to ~arsf/usr/arsf_releases/bill-YYYYMMMDD/ (where the date is the date of receiving, ish)
   1. mkdir ~arsf/usr/arsf_releases/bill-YYYYMMMDD/
   2. cd ~arsf/usr/arsf_releases/bill-YYYYMMMDD/
   3. tar xzvf ../relXXX.tar.gz
4. test it works! (need a regression test - see #12)
5. cd to ~arsf/usr/bin and symlink the new binaries there
6. ftp updated azgcorr and azexhdf to the ARSF ftp site (see internal wiki? for login details, use mgrsw user), remove old versions as needed
7. notify neodc@… + David Bell c/o serviceline@… of the update, with a short description of what it is and a link to the FTP site