Merge pull request #6 from jakubadler/master

MrowNormalizer improvements
Canonicalizer constructor changed to throw an exception when configuration stream is null instead of using the default configuration.
New test for OperatorNormalizer.
Added properties for MfencedReplacer (with test). Two new methods in AbstractModule.
Optimization (no cloning) and refactoring of MfencedReplacer.
Refactoring  (MfencedReplacer)
Added new configuration properties for MfencedReplacer
Refactoring  (MfencedReplacer) - usage of JDOM getDescendants() iterator with ElementFilter