Remove deprecated Ubuntu; updated changelog

Closes #11 and #13.  As mentioned in #11, support for Ubuntu should
return in the future, but not explicitly.  Rather, the core of A2SERVER
itself ashould be made to run on any OS distribution for which our
requirements are met.

The goal is that any OS-specific details should be part of OS-specific
packaging or handled by the user (editing MOTD/issue files, etc.)  We
can handle those details on Debian systems because we know how to do
that when packaging for Debian.  Ubuntu, Fedora, etc. packages will have
to make their own tweaks.  This commit doesn't do all of that, but it
does mean there's one fewer things we need to worry about during the
transition.

setup/index.txt

@@ -1,9 +1,9 @@
 #! /bin/bash
 # vim: set tabstop=4 shiftwidth=4 expandtab filetype=sh:
 
-# A2SERVER master setup script, last update 15-Feb-2015
+# A2SERVER master setup script, last update 17-Nov-15
 # it downloads and executes several scripts related to the setup of
-# netatalk configured for Apple II use on Debian, Raspbian, or Ubuntu.
+# netatalk configured for Apple II use on Debian or Raspbian.
 # more info is at http://appleii.ivanx.com/a2server
 
 # to download and execute, type:
@@ -102,8 +102,6 @@ if [[ $isRpi ]]; then #supported Raspbian? (16-Feb-15, 20-Jun-14, 09-Jan-14, etc
             -960832a6c2590635216c296b6ee0bebf67b21d50-"
     [[ "$fwsupported" == *-$fwhash-* ]] && unsupportedOS=0
     [[ ($fwhash == "8aca5762") || ($fwhash == "462f3e3f476f7b6") || ($fwhash == "c32bc633039cd9") || ($fwhash == "9d34d0475f9") || ($fwhash == "d4f5315cfac4e") || ($fwhash == "6f4a90c8cb8817f") || ($fwhash == "5dd9b4962e") || ($fwhash == "17c8799375") ]] && unsupportedOS=0
-elif [[ "$(lsb_release -rs 2> /dev/null)" == "12.04" ]]; then #Ubuntu 12.04?
-    unsupportedOS=0
 elif [[ "$(lsb_release -rs 2> /dev/null)" == "7.3" || "$(lsb_release -rs 2> /dev/null)" == "7.6" || "$(lsb_release -rs 2> /dev/null)" == "7.8" ]]; then # tested Debian?
     unsupportedOS=0
 fi