Issue #254 Minor fix grammar.
Issue #254 Reorder sentences/paragraphs regarding license.
Issue #254 Separate API reference from higher-level reference again.
Issue #254 Add/Fix links to separate API reference page to index and README.
Issue #250 Fix some Sphinx errors if <vendor> not specified and make API reference a separate page.
Merge commit '2cb5477963fa4529f64831ced2c4db5c72c97fa3' into develop