Added logging of every request to ProcessEngine.
Added commented line in web.config to exclude these request logs.
Added ClientException and replaced appropriate UserException and FrameworkException instances with it.
Small changes to ProcessingEngine exception handling logic.
Rhetos server will now properly recognize when server process lacks MS SQL permissions and report adequate error.
Added friendly error messages for authentication and permission problems while running Rhetos under IISExpress
Merge branch 'master' of https://github.com/sstublic/Rhetos

Conflicts:
	Source/Rhetos.Deployment/DataMigration.cs
Lessened changes in logging.