Add support for top-level enums
Remove apparently dead `file!` method

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Fix automatic rebase.

The automatic rebase of 2a0327505200717148667d57c8690397853acc1b
failed and left garbage in the generator file.
Cull whitespace and improve consistency.

A batch run of removing stray whitespace has been performed against the
codebase as well as the comments around generation code have been made
more consistent.
Include Beefcake injections for nested types.

Explicitly ensure that the preamble for generated classes and their
nested types include Beefcake's injected generated class behavior.

Commit ec102f8cf37626827a395a856758b970c47898ca introduced a
regression whereby said nested classes lost these injections.

The canonical example from https://developers.google.com/protocol-buffers/docs/overview
no longer worked.
Merge pull request #34 from protobuf-ruby/feature/generation/top-level-enums

Support Top-Level Enums