canviz.js: Add debug message and a "broken image" graphic when an image can't be loaded. See issue #33.
canviz.js: Add debug message and a "broken image" graphic when an image can't be loaded. See issue #33.


git-svn-id: d236aa11b63010c45751038f21095274a1190d52@204 96afbf3d-d051-0410-af9b-0f47d9322047

svn2github/canviz,svn2github/canviz,svn2github/canviz