[PATCH 0 of 5] keyword cleanups

[Christian Ebert]

Hi,

Here are some enhancements for the keyword extension:

- regroup monkeypatches that have accumulated over time
  by moving them into uisetup and reposetup
- reduce optional argument bloat when calling wrapped functions
- use mandatory arguments wherever possible

As additional security measure only allow expansion if there
is no \0 string in the _entire_ file (issue1066, 1079).
We are cheating the dirstate at commit, so better safe than
sorry.
This last patch is only needed if util.binary stays as it is.

c