- Detect mix of dos and unix line endings and fail with an error
- Tolerate a mix of dos and unix line endings
- read_until_match() is slow when it has to read more data, because it
  restarts the search at the top of the buffer, leading to exponential
  slowdown
- The above 3 issues were observed while investigating an email from
  Pali Rohár <pali.rohar@gmail.com>

- After Module::Install support CPAN::Meta 2.0, specify gpl_2 as the license.
  Suggested by Paul Howarth <paul@city-fan.org>
- After Module::Install support CPAN::Meta 2.0, add info for repository URL
  and bug tracker. Suggested by Paul Howarth <paul@city-fan.org>
- Wrong assumption parsing Multipart/Mixed messages
  https://rt.cpan.org/Ticket/Display.html?id=19817
- thousands of warnings during tests
  https://rt.cpan.org/Ticket/Display.html?id=13134
- Add compression support to grep
- Add random access (email Tassilo von Parseval
  <tassilo.parseval@post.rwth-aachen.de>)
- Cache, Cache::Cache
- When the subclasses call read_next_email, shouldn't the entry be validated?
- Version the cache file, so that we can invalidate it if a release of the
  module fixes a bug.
- As it is now, if we re-initialize the cache, we start all caching over. Fix
  this so that we can use partial cache information. See MetaInfo.pm