Use virtualenv2 in tests/wpt/run.sh if installed
Merge pull request #3271 from duncankl/virtualenv2-fix

Use virtualenv2 in tests/wpt/run.sh if installed
Move Attr helper methods to AttrHelpers trait to avoid to touch them from layout task.
Move Attr::local_name() to AttrHelpers/AttrHelpersForLayout.
Merge pull request #3274 from saneyuki/attr

Move Attr::set_value and Attr::value out of the Attr impl
Fix loading of file URLs with spaces
Merge pull request #3280 from metajack/path-with-spaces

Fix loading of file URLs with spaces
Return error when unable to create a file path from url.
net: Premultiply alpha in PNGs.

Closes #2857.
Run build-cef last so that tests don't cause a rebuild.
Merge pull request #3281 from pcwalton/premultiply-alpha

net: Premultiply alpha in PNGs.
Merge pull request #3284 from glennw/file-loader-fix

Return error when unable to create a file path from url.
Merge pull request #3285 from metajack/reseq-travis

Run build-cef last so that tests don't cause a rebuild.
remove unnecessary proc from resource loader factory
create about_loader, handle about:blank