Make path, node kwtemplater attribs Avoid lambda in keyword substitution.

Simplify backward compatible import For an extension it's not worth the trouble to try for demandload.

kwfmatcher first check for commit

Incorporate changes in self_initializing_hook branch Implement configurable expansion based on Mercurial templates. NOTE: Relying on pretxncommit-hook to write in working directory might break in the future as it relies on a buggy race condidition. [issue273]