Provide clarification that fields in the schema are case sensitive

[philipashlock]

This should be a pull request, but figured I'd start here. Possible text to include on the schema page:

The Project Open Data schema is case sensitive. The schema uses a camel case convention where the first letter of some words within a field are capitalized (usually all words but the first one). While it may seem subtle which characters are uppercase and lowercase, it is necessary to follow the exact same casing as defined in the schema documented here.

We could follow this with some examples, eg

Correct: contactPoint
Incorrect: ContactPoint
Incorrect: contactpoint
incorrect: CONTACTPOINT

Ideally this clarification would explain the specific rules of the convention as being lower camel case (the first letter of all words are capitalized except the first word) rather than use the words "some" and "usually" but unfortunately we break that consistency because of issue #284

[haleyvandyck]

Thanks @philipashlock -- I think this looks fine on my end. Anyone else have thoughts?

[haleyvandyck]

closing this given that #305 covered this. thanks!