Make convert test fixtures less sloppy

There were some compile errors and other odds and ends that I didn't find
when I was initially writing these. The whole point of this exercise was to
enable other people to write clean, clear tests with Ginkgo, so there's no
value in writing the tests for this feature in such a slapdash fashion.
Reorder test statements

This commit puts the func init() statement after the imports, but
before any other statements in a testfile. This should make it easier
to switch to using the var _ = Describe("test description here") syntax.
Consolidate some ginkgo-specific node funcs
Use `var _ = Describe("")` in lieu of `func init() { }`
Merge pull request #36 from tjarratt/from-the-desc-of-mr-underscore

Use `var _ = Describe()` instead of `func init() { }`