Merge pull request #33 from buxx/pyup-scheduled-update-2018-04-16

requirements.txt

 future==0.16.0
 numpy==1.14.2
 pluggy==0.6.0
-psutil==5.4.3
+psutil==5.4.4
 py==1.5.3
-pyglet==1.3.1
+pyglet==1.3.2
 pytest==3.5.0
 python-dateutil==2.7.2
 PyYAML==3.12
 redis==2.10.6
 six==1.11.0
 tmx==1.9.1
-pytest-mock==1.8.0
+pytest-mock==1.9.0
 Pillow==5.1.0