dirstate: avoid use of zip on big lists In a clean working directory containing 170,000 tracked files, this improves performance of "hg --time diff" from 1.69 seconds to 1.43. This idea is due to Siddharth Agarwal.

dirstate: move file type filtering to its source This prepares us to move to a much faster statfiles implementation on Unix.

clfilter: rename `unfilteredmeth` to `unfilteredmethod` As originally intended.

clfilter: fix a false positive in the test-obsolete.t We push between two repo which once filtered looks unrelated. Weakness in the current implementation allows this push to be done without -f. But later improvement with filtering will make this push fails for unrelatedness. However we want this push to fail for including bumped changeset. So we had a smaller push --force to make them related.

clfilter: ensure that filecache on localrepo is unfiltered All filecache usage on repo is for logic that should be unfiltered. The caches should be common to all filtered instances, and computation must be done unfiltered. A dedicated storecache subclass is created for this purpose.

clfilter: add a propertycache that must be unfiltered Some of the localrepo property caches must be computed unfiltered and stored globally. Some others must see the filtered version and store data relative to the current filtering. This changeset introduces two classes `unfilteredpropertycache` and `filteredpropertycache` for this purpose. A new function `hasunfilteredcache` is introduced for unambiguous checking for cached values on unfiltered repos. A few tweaks are made to the property cache class to allow overriding the way the computed value is stored on the object. Some logic relative to _tagcaches is cleaned up in the process.