Add GitAdapter#initRepo and a test.
Have #initRepo create an initial commit.
Revert "Have #initRepo create an initial commit."

Oops, that was the job of Versioner!

This reverts commit ca34b8f81cc8f0da184f8ffa776469a27b318c02.
Refactor and make pass tests.
Test for a commit being made by GitAdapter#commitEverything.

This involves quite a few modifications to git_adapter_test.js
Test for the author of the commit.
Refactor / flatten tests for #initRepo.
Add lodash.
Add GitAdapter#listCommits.

The tests are modified to assure that a new temporary directory is created each
time.
Expect GitAdapter#listCommits to return `sha`, `message`.
Add a test / implementation for GitAdapter#revertCommit.
Add missing semicolon.
Add spec-less #cloneRepo, #pullRepo implementations.
Clarify #listCommits documentation.