Merge pull request #38 from buxx/pyup-scheduled-update-2018-06-11

requirements.txt

 Dijkstar==2.4.0
 freezegun==0.3.10
 future==0.16.0
-numpy==1.14.3
+numpy==1.14.4
 pluggy==0.6.0
-psutil==5.4.4
+psutil==5.4.6
 py==1.5.3
 pyglet==1.3.2
-pytest==3.6.0
+pytest==3.6.1
 python-dateutil==2.7.3
 PyYAML==3.12
 redis==2.10.6