Removing Glencoe link & pointing ppl at homebrew
Tidying suggested by Mark
Removing out-of-date ref to tar.bz2 files
Tidying Windows installation page while I'm at it
ICE -> Ice
Missed one! ICE -> Ice
Merge pull request #607 from hflynn/glencoe_link

Removing link to out-of-date Ice binaries at Glencoe