Mary Barnes' nits

Text is:

"- Section 1.2.5, 2nd para, last sentence: this sentence is a bit tough
to interpret on a first read.  I would suggest rewording something
like the following:
OLD:
  This layer is to the Message Transport Layer as link-
   level congestion control and retransmission in modern wireless
   networks is to Internet transport protocols.
NEW:
   The relation of this layer to the Message Transport Layer
   "is similar to"|"can be likened to" the relation of the link-
   level congestion control and retransmission in modern wireless
   networks to Internet transport protocols.

- Section 3.4, last paragraph, 4th sentence: "in accord" -> "in
  accordance"

- Section 10.1, 2nd paragraph, 5th sentence: "can be thought of a
doubly-linked list" -> "can be thought of as a doubly-linked list"

- Section 15, last paragraph: "help resolve" -> "helped resolve""

- Text modified as suggested.
Merge pull request #192 from petithug/mary-barnes-nits

Mary Barnes' nits