Rewrite of 4.1.3 Verb

As a sort of ‘clean slate decision' I left out references to previous
versions of the spec. I feel this has only a historic meaning to the
limited number of people that are aware of / were involved in previous
versions of the spec. In anyone feels this should be included, leave a
comment.

Possible confusion: The description of the ID property says a URI should
be human-readable. Yet, "tag:example.com,2012:xQr73H" is given as an URI
example a little earlier and that is not very human-readable. Is this a
contradiction?
Added: Reading guidelines for the non-technically inclined.

One of my intentions is to make this technical document as
'approachable' as possible for folks such as instructional designers,
project managers or even commercial people. To address them directly, I
added this little paragraph.
made this line more generic.
made some corrections based on Andrew's comments
removed unclear example

as agreed with Andrew.
Merge pull request #91 from paul-esch/master

rewrite of 3.1.4 Verb, and a small note to the not-so-technical readers.