Merge pull request #198 from rjwright/TextShadowInterpTest

Make text shadow interp test pass
Merge pull request #199 from rjwright/BGPosOriginInterpTest

Make background position origin interp test pass
# This is a combination of 2 commits.
# The first commit's message is:

Make orphans, widows, background-pos-origin interp test pass

# This is the 2nd commit message:

Make widows interpolation test pass
Make orphans, widows, background-pos-origin interp test pass

Make widows interpolation test pass

clean up after merge

Make widows interpolation test pass

Make the background-position-origin test pass

Clean up after rebase
Make transform none and transform rotate interp tests pass