add prechangegroup and pretxnchangegroup hooks. prechangegroup lets you stop push, pull or unbundle before it begins. pretxnchangegroup lets you inspect changegroup before transaction is committed, and roll back if you not like it.

merge with crew.

add -w and -p options to diff. this is for issue 126.

fix names of parent changeset ids in hooks. fix hook part of man page.

prefix hook env var names with HG_. old names are still provided, but doc says they deprecated.

merge with crew

add a -b/--branch option to 'hg parents'

Fix diff against an empty file (issue124) and add a test for this.

catch errors and throw exception with invalid binary patch data

add pretxncommit hook. hook allows check of changeset after create, but before transaction is committed. hook failure rolls transaction back. makes place for local policies like commit message must contain bug id or reviewer signoff. change also adds parent changeset ids to commit hook environment, because is cheap and useful.