1.18.3: the looks' themes fetchable on their own

The Windows XP, Vista and 7 themes that the looks switch GTK and Qt programs to -- B00merang's GTK themes and icons and the Windows 7 Kvantum theme -- now come from a script of their own, tools/fetch-themes.sh. The installer still fetches them, and a copy put in with a plain make install, which fetches nothing, can be given them by running the script. Nothing is fetched twice.

curl -sL jacktulli.github.io/w2k | sh