test: fix dev dependencies and tests

Fix up dev dependencies. `npm install` works now without peer conflicts.
Tests pass on Karma ~0.12
fix: Include assertion details in chrome error reports

Run 'grunt build' so that the fix in
https://github.com/karma-runner/karma-nodeunit/commit/c6c290705cfd877577fbfc96aec5bb2341f27b69
applies for real.