hg: establish a cache for localrepository instances hgweb contained code for determining whether a cached localrepository instance was up to date. This code was way too low-level to be in hgweb. This functionality has been moved to a new "cachedlocalrepo" class in hg.py. The code has been changed slightly to facilitate use inside a class. hgweb has been refactored to use the new API. As part of this refactor, hgweb.repo no longer exists! We're very close to using a distinct repo instance per thread. The new cache records state when it is created. This intelligence prevents an extra localrepository from being created on the first hgweb request. This is why some redundant output from test-extension.t has gone away.