sqm-scripts: syncronise changes made for Openwrt pull request

This commit includes the Makefile changes & small menu/typo fixes
done for the Openwrt pull request.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>
Merge pull request #10 from hnyman/sqm-for-openwrt

sqm-scripts: syncronise changes made for Openwrt pull request