Removed unused case OTClient::issueAssetType.
Removed unused case OTClient::sendUserMessage.
Removed unused case OTClient::checkUser.
Merge pull request #334 from benma/ProcessUserCommand

Start removing dead code from OTClient::ProcessUserCommand.
reorder methods
Add strategy manager
add OTMessage::processXmlSuccess

for refactoring only. Will be deleted later.
processXml uses OTMessage param, part 0
processXml uses OTMessage param, part 1
writeXmlXXX uses OTMessage param, part 0
writeXmlXXX uses OTMessage param, part 1
writeXmlXXX uses OTMessage param, part 2
rewrite usage of writeXml
Convert methods to strategy classes, part 1
Convert methods to strategy classes, part 2
format code
remove calling old methods
move the code
remove helper stuff from header
remove OTMessage::processXmlSuccess