Support pending specs with:
- xit
- it with a null function body ( it("should be pending");
- calling pending() inside a spec
- having a spec without any expectations

Pending and Filtered specs now call Reporter interface specStarted so that reporting acts as expected.
Pending and Filtered spec names are present and styled in the HTML reporter

Using xit used to disable a spec. Disabling is now just when a spec is filtered out at run time (usually w/ the reporter).

Suites are still disabled with xdescribe and means its specs are never executed.
Protect against a FF bug: Exceptions don't always have a message property even though they were instantiated with one. Using Error#toString alleviates this