diff: add --stat for diffstat output
diff/qdiff --stat invokes patch.diffstat() on the diff output.
When in interactive mode, the output's maximum width is determined by the
terminal's width.
#!/bin/sh
hg init a
cd a
hg log
hg grep wah
hg manifest
hg verify
ls .hg
ls .hg/store
cd ..
hg clone a b
cd b
hg verify
ls .hg
ls .hg/store