Changed all MatchResult in HaveWord to construct error message lazily.
Changed all MatchResult in IncludeWord to construct error message lazily.
Added nice toString to BeWord, BehaveWord, ContainWord, DefinedWord, EmptyWord, EndWithWord, FullyMatchWord, HaveWord, IncludeWord and LengthWord.
Changed all MatchResult in MatcherWords to construct error message lazily, and make returned MatcherFactory1/Matcher to have pretty toString.
Added pretty toString to NoExceptionWord.
Changed all MatchResult in MatcherWords to construct error message lazily, and use pretty toString for Matcher/MatcherFactory.  Fixed a deteched bug in MatchResult's negated function and also in NotWord where added diffString in places that it should be called.
Completed lazy MatchResult and pretty toString refactoring in NotWord and some of its related word classes.
Merge branch 'lazy-msg-4' of https://github.com/cheeseng/scalatest