fix 'undefined name 'buffer'' on Python 3.x
add target to lint for Python 2 and 3
add fallback localStorage implementation if not functional, #134
use /opt/isso as virtualenv and add a simple sysvinit script

The SysVinit script is not tested, but it looks fine to me. Also added a
few lines on how to execute `isso` when using a virtualenv from the
outside (both changes suggested on IRC).