Build: Excanvas to Bower dependency

Remove checked in copy of Excanvas with bower install.
Minor task cleanup for bower.
Build: Bump assemble version

Some people reported errors because the 0.4.4 didn't include the new
i18n additions.
Merge pull request #2999 from nschonni/excanvas-to-bower

Build additions: i18n and Excanvas

Thanks @nschonni, nice addition and cleanup