Support gomega without ginkgo

[nunnatsa]

This PR adds support for cases when using gomega directly, without ginkgo.

For example:

func TestSomething(t *testing.T) {
    g := NewGomegaWithT(t)

    var err error
    g.Expect(err).ToNot(BeNil())
}

[coveralls]

Pull Request Test Coverage Report for Build 3924305016

• 12 of 65 (18.46%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-6.8%) to 79.935%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
gomegahandler/handler.go	12	65	18.46%
<!--	Total:	12	65	18.46%	-->

Totals
Change from base Build 3638204896:	-6.8%
Covered Lines:	490
Relevant Lines:	613

---

💛 - Coveralls