Move cmdtable and reposetup handling out of extensions.py
A new function (extensions.extensions) allows the code that is
interested in those attributes to handle them directly.
This allows some cleanups of extensions.py. Notably, we can
remove the extensions.commandtable hack.
It also makes it easier to add standard extension attributes,
like a "hgwebsetup" function or a "helptable" dict that augments
the data in help.py, etc.
#!/bin/sh
hg init a
cd a
echo 'root' >root
hg add root
hg commit -d '0 0' -u test -m "Adding root node"
echo 'a' >a
hg add a
hg branch a
hg commit -d '1 0' -u test -m "Adding a branch"
hg update -C 0
echo 'b' >b
hg add b
hg branch b
hg commit -d '2 0' -u test -m "Adding b branch"
echo 'bh1' >bh1
hg add bh1
hg commit -d '3 0' -u test -m "Adding b branch head 1"
hg update -C 2
echo 'bh2' >bh2
hg add bh2
hg commit -d '4 0' -u test -m "Adding b branch head 2"
echo 'c' >c
hg add c
hg branch c
hg commit -d '5 0' -u test -m "Adding c branch"
hg branches
echo '-------'
hg branches -a