Use consistent version references

Use consistent version references

A simple clean-up where the version references have been unified
all those places I could find now.  The versioning scheme used is:

    * OpenVPN 2.x
    * v2.x

We want to avoid:
    * 2.x  (2.4 can be just an ordindary decimal number,
            OID reference, a version number or anything else)
    * OpenVPN v2.x (OpenVPN indicates we're talking about a version)

In addition, several places where it made sense I tried to ensure
the first version reference uses "OpenVPN 2.x" and the following
references in the same section/paragraph uses "v2.x", to set the
context for the version reference.

In Changes.rst modified paragraphs exceeding 80 chars lines where
reformatted as well.

Signed-off-by: David Sommerseth <davids@openvpn.net>
Acked-by: Steffan Karger <steffan@karger.me>
Message-Id: <20170815205301.14542-1-davids@openvpn.net>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15260.html
Signed-off-by: David Sommerseth <davids@openvpn.net>
(cherry picked from commit 500854c3fc956b274790991e4d6771ad9bf6f641)