Differences in functionality in inprocess hooks for CLI and API

[Chris Scott]

> If you want to use Python as a portable shell, that's totally doable by 
> simply setting your hook like so:
> 
> [hooks]
> pretxnchangegroup = python myhook.py 
>
> ..which will invoke the aforementioned magic properly.

This is what we may wind up doing, but the idea was to be able to run hooks without needing a full python installation locally.  Presumably hg can launch it without a full python installed.  It would be nice if there was some syntax in the hook command to indicate that your hook was a python script to be run in a new-process but in launched via hg's own python26.dll.  Admittedly, this is only a headache on the Windows distributions, which is the only major operating system not to come bundled with standard scripting tools.  

Then all hooks could take advantage of the pretxn hg magic that hg does.

~Chris