Update README

Update URL from http://www.ddj.com/ddj/1997/careers1/wil2.htm to http://www.drdobbs.com/keys-to-the-kingdom/184410429
Update GuiTest.pm

Update URL from http://www.ddj.com/ddj/1997/careers1/wil2.htm to http://www.drdobbs.com/keys-to-the-kingdom/184410429
Update GuiText.xs

Update URL from http://www.ddj.com/ddj/1997/careers1/wil2.htm to http://www.drdobbs.com/keys-to-the-kingdom/184410429
Merge pull request #3 from MartinMcGrath/master

Update URL for Dr Dobb's article