feat(matchers): add haveClass matcher to test node classes
fix(browser): handle properly server errors response
test(widgets): add integration tests for examples viewer
style(browser): better styles for the runner header and progress
style(browser): add tests counter in list header
style(browser): adjust count padding in header
feat(browser): add a search box in the the list header

The search is performed using the CSS trick described in
http://redotheweb.com/2013/05/15/client-side-full-text-search-in-css.htm
l .