Convert tests to casper API (bug 1045707)

This converts us over to using the casper 1.1 api directly and removes the abstraction layer and updates everything to the current version of casper which is 1.1-beta3
+1 on this suggestion. Depends on the version of bash used, if it doesn't work, maybe use `` `find tests/ui -name '*.js'` `` (with the backticks) as argument to casper instead.