match: remove support for includes from patternmatcher Includes (and excludes) are now delegated to the includematcher.

match: simplify includematcher a bit The "include" we have in symbols is redundant and the double negative in visitdir() can be removed.

match: remove support for non-include patterns from includematcher The includematcher will always get at least one include pattern and will never get any non-include patterns, so we can remove most of the code in it. This patch does mostly straight-forward deletions of code. We will clean up further later.

match: split up main matcher into patternmatcher and includematcher At this point the includematcher is an exact copy of the main matcher class. We will specialize and simplify both classes in the following patches. This initial unmodified copy is just to make the differences clearer. We also rename the main matcher to "patternmatcher" for consistency. I may eventually merge this new includematcher back into the main matcher, but I think doing it this way makes the intermediate steps clearer regardless.

match: remove support for exact matching from main matcher class Exact matching is now handled by the exactmatcher class. We can safely remove _files from the __repr__() implementation, because even though the field is set, the patternspat field is enough for the representation to be unambiguous (which was not the case when the matcher could handle exact matches).

match: handle exact matching using new exactmatcher