Dispatcher : Refactored

I closed the previous pull request by mistakenly. So creating a new one.
1. Here I've added HandlerConfigurator to handle Handler.config file.
2.Removed Mapper and HandlerMappings,instead moved Handler.config file's contents to dictionary so that mapping can be found directly using key,no need to iterate through.
3.Refactored Dispatcher to maintain <20 lines code per function
4.Changed Handler.config file's structure,used comma separated extensions for static handler.
5.Changed Custom Exception Implementation