Fix SRM download issues on windows/mingw

Files were read/written in ascii mode so mingw/windows mangled line-breaks and corrupted the data.

First commit fixes this in GC - but the more important fixes are in srmio/master. So, please update the build environments. There's another fix for bad markers when data was split in latest srmio, as well. I'll prepare a tar with a snapshot of srmio, next. Will show up as http://www.zuto.de/project/files/srmio/srmio-0.1.1~git1.tar.gz

I've added another hunk that includes the srmio version in the about dialog - it requires latest srmio.