tests/test-mq-qsave

Make tests append settings to $HGRCPATH instead of $HGTMP/.hgrc
and add documentation for this.

#!/bin/sh

echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH

hg init a
cd a

echo 'base' > base
hg ci -Ambase -d '1 0'

hg qnew -mmqbase mqbase

hg qsave
hg qrestore 2