Removed unused/obsolete request/screen context fields.



git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1621801 13f79535-47bb-0310-9956-ffa450edef68
A series of clean-ups and modifications to RequestHandler, EventFactory and View Factory to make then (mostly) immutable and eliminate some potential concurrency issues that could happen at initialization. This is just a first pass.


git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1621804 13f79535-47bb-0310-9956-ffa450edef68