Release 1.2.0 Preparation

* README.txt -> README.md: renamed
	* dtls/sslconnection.py: Reduce the default MTU in effect while
    handshaking to 576, suitable for various path MTUs and PPPoE
	* dtls/prebuilt/win32-x86[_64]: Rebuilt with Visual C++ 2008 to
    eliminate requirement to install a C++ redistributable package
	* dtls/prebuilt/mingw-x86: mingw support is deprecated
	* dtls/__init__.py: VERSION introduced
	* setup.py: Version incremented to 1.2.0

dtls/prebuilt/mingw-x86/manifest.pycfg

@@ -1,33 +0,0 @@
-# Prebuilt directory manifest.
-
-# Copyright 2012 Ray Brown
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# The License is also distributed with this work in the file named "LICENSE."
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# This file is executed by the distribution builder, as well as the dtls
-# package startup code; the purpose of the latter is being able to run
-# from a cloned source directory without executing any sort of installation
-# procedure. This file provides the definitions required to create
-# a distribution including this directory's prebuilts.
-
-from os import path
-from glob import glob
-
-assert MANIFEST_DIR
-
-ARCHITECTURE = "mingw-win32"
-FORMATS = "gztar"
-FILES = map(lambda x: path.basename(x),
-            glob(path.join(MANIFEST_DIR, "*.dll")))