updated reqs for security

app/requirements.txt

@@ -2,13 +2,13 @@ backports-abc==0.4
 bokeh==0.10.0
 certifi==2016.9.26
 click==6.6
-Flask==0.11.1
+flask>=1.0.0
 Flask-SocketIO==2.7.1
 gevent==1.1.2
 greenlet==0.4.10
 influxdb==4.1.0
 itsdangerous==0.24
-Jinja2==2.8
+Jinja2>=2.10.1
 MarkupSafe==0.23
 numpy==1.11.1
 pandas==0.18.1
@@ -16,9 +16,9 @@ python-dateutil==2.5.3
 python-engineio==1.0.3
 python-socketio==1.6.0
 pytz==2016.6.1
-PyYAML==3.12
+pyyaml>=4.2b1
 pyzmq==15.4.0
-requests==2.11.1
+requests>=2.20.0
 singledispatch==3.4.0.3
 six==1.10.0
 socketIO-client==0.7.0