fixed build errors - a whole bunch of spec links & ref file links
fixed spec links to not be prodefs
Add reference file for background-origin
Move images/ files to support/
Remove useless readme file
Move reftest/ ref files to reference/
merge
Move resource/ files to support/

- Remove two useless images
- Move css3.png to support
Merge pull request #565 from chenxix/chenxix/csswg-test/background-origin

Add reference file for background-origin
Merge pull request #577 from chenxix/chenxix/csswg-test/remove-images

Move images/ files to support/
Merge pull request #576 from chenxix/chenxix/csswg-test/remove-reftest

Move two ref files from reftest folder to reference
Merge pull request #575 from chenxix/chenxix/csswg-test/remove-readme

Remove useless readme file
Merge pull request #578 from chenxix/chenxix/csswg-test/remove-resource

Move resource/ files to support/