Updated shebang line

Not everyone has SBCL installed in /usr/bin/sbcl and sometimes one wants to test other versions of SBCL or just not install the official Debian/Ubuntu packages. I have tested this on Ubuntu precise and it worked for me.

I got the info this would work from here:
https://bugs.launchpad.net/sbcl/+bug/1284148
Merge pull request #41 from JimPanic/patch-2

Updated shebang line