Update Dialog.rb
Fix reserved word for IE
Remove redundant code and update version to 1.0.15
newer versions of Base.js, Dialog.rb, Options.rb, Translate.rb
update
• feature testing for older SketchUp versions (`respond_to?`)
• use `$stderr.write` instead of `puts` for errors
• use of newer Dialog.rb features `call_function`
removal of unnecessary comment