Fixes #44

Removed both W3C Nu Validation Service (and the new window), renamed W3C
Nu Validation Service to 'Markup Checker', adjusted documentation as
well
Follow up to Fix #32

Added code to handle changes in IE 11 (versus prior versions), for View
Partial Source
Merge pull request #55 from menovak/master

Further #32 enhancements; Validation service (fixes #44)