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
# test parents command
hg init repo
cd repo
echo % no working directory
hg parents
echo a > a
echo b > b
hg ci -Amab -d '0 0'
echo a >> a
hg ci -Ama -d '1 0'
echo b >> b
hg ci -Amb -d '2 0'
echo % hg parents
hg parents
echo % hg parents a
hg parents a
echo % hg parents -r 2
hg parents -r 2
echo % hg parents -r 2 a
hg parents -r 2 a
echo % hg parents -r 2 ../a
hg parents -r 2 ../a
echo '% cd dir; hg parents -r 2 ../a'
mkdir dir
cd dir
hg parents -r 2 ../a
echo '% hg parents -r 2 path:a'
hg parents -r 2 path:a
echo '% hg parents -r 2 glob:a'
cd ..
hg parents -r 2 glob:a
true