[WIP] - Libssh2 based clients (#86)

* Added ssh2 native library based parallel and single clients, library refactoring for code reuse.
* Added openssh based embedded server for testing and test client keys.
* Added get_last_output function and cmds attribute to parallel clients and tests.
 Updated changelog, documentation.
* Added contribution guide, code of conduct, issue template.

.appveyor.yml

@@ -0,0 +1,106 @@
+environment:
+  global:
+    # SDK v7.0 MSVC Express 2008's SetEnv.cmd script will fail if the
+    # /E:ON and /V:ON options are not enabled in the batch script intepreter
+    # See: http://stackoverflow.com/a/13751649/163740
+    CMD_IN_ENV: "cmd /E:ON /V:ON /C %APPVEYOR_BUILD_FOLDER%\\ci\\appveyor\\run_with_env.cmd"
+    PYTHONUNBUFFERED: 1
+    PYPI_USER:
+      secure: 2m0jy6JD/R9RExIosOT6YA==
+    PYPI_PASS:
+      secure: x+dF0A8BZUf2IrPNRN1O0w==
+  matrix:
+    - PYTHON: "C:\\Python27"
+      PYTHON_VERSION: "2.7"
+      PYTHON_ARCH: "32"
+      MSVC: "Visual Studio 9"
+
+    - PYTHON: "C:\\Python27-x64"
+      PYTHON_VERSION: "2.7"
+      PYTHON_ARCH: "64"
+      MSVC: "Visual Studio 9"
+
+    - PYTHON: "C:\\Python34"
+      PYTHON_VERSION: "3.4"
+      PYTHON_ARCH: "32"
+      MSVC: "Visual Studio 10"
+
+    - PYTHON: "C:\\Python34-x64"
+      PYTHON_VERSION: "3.4"
+      PYTHON_ARCH: "64"
+      MSVC: "Visual Studio 10 Win64"
+
+    - PYTHON: "C:\\Python35"
+      PYTHON_VERSION: "3.5"
+      PYTHON_ARCH: "32"
+      MSVC: "Visual Studio 14"
+
+    - PYTHON: "C:\\Python35-x64"
+      PYTHON_VERSION: "3.5"
+      PYTHON_ARCH: "64"
+      MSVC: "Visual Studio 14 Win64"
+
+    - PYTHON: "C:\\Python36"
+      PYTHON_VERSION: "3.6"
+      PYTHON_ARCH: "32"
+      MSVC: "Visual Studio 14"
+
+    - PYTHON: "C:\\Python36-x64"
+      PYTHON_VERSION: "3.6"
+      PYTHON_ARCH: "64"
+      MSVC: "Visual Studio 14 Win64"
+
+install:
+  # If there is a newer build queued for the same PR, cancel this one.
+  # The AppVeyor 'rollout builds' option is supposed to serve the same
+  # purpose but it is problematic because it tends to cancel builds pushed
+  # directly to master instead of just PR builds (or the converse).
+  # credits: JuliaLang developers.
+  - ps: if ($env:APPVEYOR_PULL_REQUEST_NUMBER -and $env:APPVEYOR_BUILD_NUMBER -ne ((Invoke-RestMethod `
+        https://ci.appveyor.com/api/projects/$env:APPVEYOR_ACCOUNT_NAME/$env:APPVEYOR_PROJECT_SLUG/history?recordsNumber=50).builds | `
+        Where-Object pullRequestId -eq $env:APPVEYOR_PULL_REQUEST_NUMBER)[0].buildNumber) { `
+          throw "There are newer queued builds for this pull request, failing early." }
+  - ECHO "Installed SDKs:"
+  - ps: "ls \"C:/Program Files/Microsoft SDKs/Windows\""
+
+  # Prepend newly installed Python to the PATH of this build (this cannot be
+  # done from inside the powershell script as it would require to restart
+  # the parent CMD process).
+  - "SET PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%"
+
+  # Check that we have the expected version and architecture for Python
+  - "python --version"
+  - "python -c \"import struct; print(struct.calcsize('P') * 8)\""
+
+  # Upgrade to the latest version of pip to avoid it displaying warnings
+  # about it being out of date.
+  - "pip install --disable-pip-version-check --user --upgrade pip"
+
+  - git submodule update --init --recursive
+  - "%CMD_IN_ENV% ci\\appveyor\\build_ssh2.bat"
+  # Install the build dependencies of the project. If some dependencies contain
+  # compiled extensions and are not provided as pre-built wheel packages,
+  # pip will build them from source using the MSVC compiler matching the
+  # target Python version and architecture
+  - "%CMD_IN_ENV% pip install -r requirements.txt"
+  - "%CMD_IN_ENV% pip install -U wheel setuptools twine"
+
+build_script:
+  # Build the compiled extension
+  - "%CMD_IN_ENV% python setup.py build_ext -i"
+
+test_script:
+  - python -c "import pssh.native.ssh2"
+  - python -c "import pssh.pssh2_client"
+
+after_test:
+  # If tests are successful, create binary packages for the project.
+  - "%CMD_IN_ENV% python setup.py bdist_wheel"
+  - mv dist/* .
+
+artifacts:
+  # Archive the generated packages in the ci.appveyor.com build report.
+  - path: "*.whl"
+
+deploy_script:
+  - python ci/appveyor/pypi_upload.py *.whl

.codecov.yml

@@ -0,0 +1,3 @@
+ignore:
+  - "embedded_server/.*"
+  - "tests/.*"

.coveragerc

@@ -19,3 +19,4 @@ exclude_lines =
     raise NotImplementedError
     if __name__ == .__main__.:
     logger.debug
+    continue