Merge pull request #175 from sprowell/master

Avoid re-computing the key when reading from the cache.
Merge pull request #177 from sprowell/master

Refactoring.
Merge pull request #178 from sprowell/master

Working version of compilable context.
Merge pull request #179 from sprowell/master

Re-located the `-N` flag.
Merge pull request #180 from sprowell/master

Moved test classes to test packages.
Added rewrite_aggressive_fail property, which is used in ACMatcher.
Merge pull request #181 from kirkdsayre/master

rewrite_aggressive_fail property
Dispensed with some unnecessary (?) type annotations.