* src/KeywordProcessor.php
 - Lots of code cleanup
 - KeywordChecking is now done with a regex generated at runtime, to make adding new Keywords easier.
 - added define PROCESSOR_CHECK_FOR_KEYWORDS_RE that holds the regex to check for keywords.
 - commented out regular expression replacement timing, but can be reenabled to check regex performance
READNE :
  - added  @@IGNOREKEYWORDS to README to prevent Keyword processing.

* src/processor.php :
  - code cleanup
misc code cleanup and various small changes