ADD: more request headers and Json response MIME type
FIX: renamed NormalResponse to HtmlResponse and StaticResponse to GzipResponse
FIX: replaced hardcoded values w/ cpnstants. Config went from private to protected
FIX: moved code from VirtualFileSystem to StaticPages class. Added methods in VirtualFileSystem for access to KeyValueStore and static pages
FIX: refactored get method
ADD: JsonResponse
FIX: class name dependency