dispatch: parse and apply -R early
This allows us to use extensions specified in .hg/hgrc. Unfortunately,
this requires us to parse that file twice, but performance impact on
the version command appears to be less than 1%.
#!/bin/sh
hg init
echo "nothing" > a
hg add a
hg commit -m ancestor -d "1000000 0"
echo "something" > a
hg commit -m branch1 -d "1000000 0"
hg co 0
echo "something else" > a
hg commit -m branch2 -d "1000000 0"
hg merge 1
hg id
cat a
hg status