Grammar: "they're" → "there".
Capitalization.
Capitalization and grammar.
Consistency: "GitHub".
Language.
Punctuation.
Consistency: "Windows".
Consistency: "GNU".
Grammar: "its" → "it's" (where applicable).
Capitalization.
Consistency: "Git".
Consistency: "OS X".
Punctuation.
Consistency: "Vim".
Consistency: "Unix".
Fix bad change in f11d50b.
Merge pull request #2 from dandersson/grammar-and-consistency

Mostly grammar and consistency changes