Fixed many Sonar warnings :
o Useless null checks
o Bad switch.. case handling with useless fallbacks 
o Removed commented code
o Improved some Map parsing
o Removed the AbstractChemaLoader listener, as it's never used and potantially not thread safe
o Fixed some signed byte manipulations

git-svn-id: https://svn.apache.org/repos/asf/directory/shared/trunk@1485295 13f79535-47bb-0310-9956-ffa450edef68