commands/fetch_git_commits: stubs for git log fetching
git_commit: add git commit object
git_commit_parser: add git log parser code
fetch_git_commits: add code to get commits
git/ui: add the git setter ui
cli_interface: add git ui
git_ui: fix typo
git_ui: remove extra gets, add show command
commands/fetch_git_commits: make commits accessor
git_commit_printer: add cute printer for git commit logs
ui/git_ui: add author for commit printing
ui/invoice_ui: add commit printing for invoice
git_commit_parser: change gitlog to gitcommit
git_commit_printer: niceify printing
git_ui: also print author on ls
git_ui: fix silly typo (get, not author)
invoice_ui: niceify the printing of git commit logs.

This commit concludes #25