branch: review

* minor English language issues
'orrible English
the case of 'close'...

'close' is a confusing condition/word (because it is also an action, which can be especially confusing in a robotic context!).

The correct, accurate word should have been 'nearby' (and associated "is nearby", ...). but I refrained from renaming all the constants (although the change should have no impact...) Related issues: SYM_CLOSE.

So I think a discrete comment might help casual readers.

Similar issue for EVENT_IS_ARRIVED. Bad English, should have been EVENT_HAS_ARRIVED. But such a change could have an impact on the "is/is not" logic used elsewhere.
even if it is a commented message...
the file, the this, the that... Avoid useless wordings.

Error messages should be succint, error logs should be *dense* rather than eat up disk space: putting 'the' everywhere is a *HUGE* waste of (brain) bytes.
Some improvements
Alex review
Merge branch 'review-2' of https://github.com/axd1967/PC

Conflicts:
	Bin/NSReference.md
Change sharp sensor values: off, on, nearby.
Improves reference opening.