Add first draft Git Concepts
Correct spelling error
Append "$" before each command line example
Recraft content to focus on GitHub flow
Wording tune-up
Tune "remote" term description
Remove ".com" from GitHub platform descriptions
Remove last ".com" reference for GitHub platform
Add draft of Pull Request description
Fix terms heading format
Rename to beta for first-past merge
Remove placeholder TBD
Merge pull request #104 from github/github-concepts-md

Beta first-draft GitHub Git Concepts as Markdown