Created a class in util called chunkbuffer that buffers reads from an iterator over strings (aka chunks). Also added to util (for future use) is a generator function that iterates over a file n bytes at a time. Lastly, localrepo was changed to use this new chunkbuffer class when reading changegroups form the local repository.

Add test output.

Date validation must check for 32-bit width. Don't use assert to check.

Make date/timezone validation in changelog.add more robust. Add test.

Validate user input of dates when adding a changelog entry.

Add doc string for debugrename.

Fortify the recognition of a diff header.

Add -p to incoming and outgoing commands to show patch