First quick docs proofread

[ciaranmooney]

I went through all of the docs and gave them a quick proofread. I have tried to make them more consistent (ID everywhere instead of half "id", half "ID") and less ambiguous in places.

I have kept your original wording where possible, and have only really added one or two words. Some sentences have been removed as they did not seem to be relevant to the function.

[ntoll]

Fixed by merge. Thanks @ciaranmooney :-)