Add time-zone support to date parser (#3)

The date parser can now handle the timezone option and commas
within the option (e.g., to isolate the date format from the
timezone option).

  %date{MM/dd/yyyy HH:MM:SS, Australia/Perth}

This also splits DecoderTest into individual test suites for %date,
%level, and %logger.
Add bin/ to .gitignore
Fix chmod for .gitignore and LICENSE.txt