for too-long records, MARC::Writer still writes records ForgivingReader can read now
MARC::Writer, optional allow_oversized=false to raise on oversized writing
tests, don't try to do encoding related tests unless we're in 1.9.3
Writer, change default allow_oversized==false
Merge pull request #18 from ruby-marc/invalid_writes

Doc, spec, and fix how MARC::Writer handles too-long records