Removed duplicated array key
…ugh handler constructor
2nd fix for issue #91
… get sent to the sub-handler twice
- constants defined for the 2 missing levels: NOTICE and EMERGENCY. - add<level>() and <level>() convenience methods added. - TestHandler and tests updated to account for the two extra levels. - surjective mappings from the RFC3164 to only 6 levels changes to bijective. - README updated accordingly.