command line templates: add formatnode filter
This will print a full hash node with --debug and a short one otherwise.
Use it with some default templates and in map-cmdline.default to print
the parents. This should fix issue538.
#!/bin/sh
hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
ls
echo This is file b1 > b
hg add b
hg commit -m "commit #1" -d "1000000 0"
hg co 0
# B should disappear
ls