first attempt at windows builds, with appveyor.com

The .appveyor.yml tells the tox.ini to install pypiwin32 directly,
rather than through a "twisted[windows]" extra. I wasn't able to get the
"extra" syntax to work properly under appyeyor, even though it worked ok
for me locally.

We use an extra "meta" tox environment to run "wormhole --version". This
confirms that versioneer is getting the right value, since we're now
running it from an installed sdist, rather than a checked-out git source
tree.

.appveyor.yml

@@ -0,0 +1,65 @@
+# adapted from https://packaging.python.org/en/latest/appveyor/
+
+
+environment:
+  # we tell Tox to use "twisted[windows]", to get pypiwin32 installed
+  #TWISTED_EXTRAS: "[windows]"
+  # that didn't work (it seems to work when I run it locally, but on appveyor
+  # it fails to install the pypiwin32 package). So don't bother telling
+  # Twisted to support windows: just install it ourselves.
+  EXTRA_DEPENDENCY: "pypiwin32"
+  matrix:
+    # For Python versions available on Appveyor, see
+    # http://www.appveyor.com/docs/installed-software#python
+    - PYTHON: "C:\\Python27"
+    - PYTHON: "C:\\Python27-x64"
+    - PYTHON: "C:\\Python33"
+    - PYTHON: "C:\\Python33-x64"
+      DISTUTILS_USE_SDK: "1"
+    - PYTHON: "C:\\Python34"
+    - PYTHON: "C:\\Python34-x64"
+      DISTUTILS_USE_SDK: "1"
+    - PYTHON: "C:\\Python35"
+    - PYTHON: "C:\\Python35-x64"
+      DISTUTILS_USE_SDK: "1"
+
+# tox-2.3.1 has a windows bug (#314), fixed in hg but not yet released. When
+# the next release comes out, replace this with just:
+#   %PYTHON%\python.exe -m pip install wheel tox
+
+install:
+  - |
+    %PYTHON%\python.exe -m pip install -U pip virtualenv
+    %PYTHON%\python.exe -m pip install wheel "hg+https://bitbucket.org/hpk42/tox#egg=tox"
+
+# note:
+# %PYTHON% has: python.exe
+# %PYTHON%\Scripts has: pip.exe, tox.exe (and others installed by bare pip)
+
+
+build: off
+
+test_script:
+  # Put your test command here.
+  # Note that you must use the environment variable %PYTHON% to refer to
+  # the interpreter you're using - Appveyor does not do anything special
+  # to put the Python evrsion you want to use on PATH.
+  - |
+    misc\windows-build.cmd %PYTHON%\Scripts\tox.exe -e py,meta
+
+after_test:
+  # This step builds your wheels.
+  # Again, you only need build.cmd if you're building C extensions for
+  # 64-bit Python 3.3/3.4. And you need to use %PYTHON% to get the correct
+  # interpreter
+  - |
+    misc\windows-build.cmd %PYTHON%\python.exe setup.py bdist_wheel
+
+artifacts:
+  # bdist_wheel puts your built wheel in the dist directory
+  - path: dist\*
+
+#on_success:
+#  You can use this step to upload your artifacts to a public website.
+#  See Appveyor's documentation for more details. Or you can simply
+#  access your wheels from the Appveyor "artifacts" tab for your build.

misc/windows-build.cmd

@@ -0,0 +1,21 @@
+@echo off
+:: To build extensions for 64 bit Python 3, we need to configure environment
+:: variables to use the MSVC 2010 C++ compilers from GRMSDKX_EN_DVD.iso of:
+:: MS Windows SDK for Windows 7 and .NET Framework 4
+::
+:: More details at:
+:: https://github.com/cython/cython/wiki/64BitCythonExtensionsOnWindows
+
+IF "%DISTUTILS_USE_SDK%"=="1" (
+    ECHO Configuring environment to build with MSVC on a 64bit architecture
+    ECHO Using Windows SDK 7.1
+    "C:\Program Files\Microsoft SDKs\Windows\v7.1\Setup\WindowsSdkVer.exe" -q -version:v7.1
+    CALL "C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\SetEnv.cmd" /x64 /release
+    SET MSSdk=1
+    REM Need the following to allow tox to see the SDK compiler
+    SET TOX_TESTENV_PASSENV=DISTUTILS_USE_SDK MSSdk INCLUDE LIB
+) ELSE (
+    ECHO Using default MSVC build environment
+)
+
+CALL %*

tox.ini

@@ -13,14 +13,31 @@ skip_missing_interpreters = True
 # all builds with a copy of Twisted from git 'trunk' until Twisted-16.0.0 is
 # released and we can just depend on that.
 
+# On windows we need "pypiwin32" installed. It's supposedly possible to make
+# Twisted do this by depending upon "twisted[windows]" instead of just
+# "twisted", but when I try this via Appveyor, the extra is ignored.
+#    git+https://github.com/twisted/twisted#egg=twisted{env:TWISTED_EXTRAS:}
+#    #twisted{env:TWISTED_EXTRAS:}
+# So instead we have the .appveyor.yml set EXTRA_DEPENDENCY=pypiwin32. In
+# other environments, this variable will be empty, and tox will ignore the
+# blank value.
+
 [testenv]
 deps =
     git+https://github.com/twisted/twisted#egg=twisted
     #twisted
+    {env:EXTRA_DEPENDENCY:}
     coverage
 commands =
     trial {posargs:wormhole}
 
+# on windows, trial is installed as venv/bin/trial.py, not .exe, but (at
+# least appveyor) adds .PY to $PATHEXT. So "trial wormhole" might work on
+# windows, and certainly does on unix. To get "coverage run" to work, we need
+# a script name (since "python -m twisted.scripts.trial" doesn't have a 'if
+# __name__ == "__main__": run()' -style clause). The script name will vary on
+# the platform.
+
 [testenv:meta]
 deps =
     pyflakes