Added devcontainer to allow for easier development (#65)

Co-authored-by: Rob Bagby <robbag@microsoft.com>

.devcontainer/devcontainer.json

@@ -0,0 +1,10 @@
+{
+    "image": "python:3.5.2",
+
+    // Run Bash script in .devcontainer directory
+	"onCreateCommand": "/bin/bash .devcontainer/on-create.sh",
+	
+	"extensions": [
+		"ms-python.python"
+	]
+}

.devcontainer/on-create.sh

@@ -0,0 +1,8 @@
+python -m pip install --upgrade pip
+pip install -r requirements.txt
+pip install -r dev_requirements.txt
+pip install flake8
+flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+pip install pytest
+pytest