WSUG and image updates.

Update the protocol hierarchy, conversation, and endpoint sections of
the User's Guide. When everything is an admonition nothing stands out.
Make a series of "NOTE"s plain old paragraphs. Scale the new
conversation and endpoint images to fit the page width. This looks funny
in my browser but I'm not sure about the best way to fix it.

Move image/compress-pngs to the tools directory. Use it to reduce the
size of the WSUG and WSDG images.

Fixup traffic table column names and window titles.

Change-Id: I674342ed901fc64563b384ee5e1f35413736cb19
Reviewed-on: https://code.wireshark.org/review/7122
Reviewed-by: Gerald Combs <gerald@wireshark.org>

docbook/release-notes.asciidoc

@@ -21,6 +21,16 @@ used for troubleshooting, analysis, development and education.
 
 === New and Updated Features
 
+The following features are new (or have been significantly updated)
+since version 1.99.2:
+
+* Qt port:
+
+** Several bugs have been fixed.
+** You can now open a packet in a new window.
+** The Bluetooth ATT Server Attributes dialog has been added.
+** The Coloring Rules dialog has been added.
+
 The following features are new (or have been significantly updated)
 since version 1.99.1: