Corrected the "without gtk" reference to "./configure --without-gtk", because the previous version "--WITHOUT_GTK" caused an error.
The error message was:
    configure: error: unrecognized option: `--WITHOUT_GTK'
Also fixed a couple of README typos.
Merge pull request #63 from garethrandall/readme-fixes

Corrected the "without gtk" reference to "./configure --without-gtk", be...