Fix "No module named 'numpy.random.common'" in pyinstaller

Close #465

.travis.yml

@@ -127,6 +127,11 @@ script:
 
       # Build the standalone executable
       pip install 'pyinstaller!=3.4'  # 3.4 raises error
+
+      # numpy 1.17 raises error
+      # See https://github.com/wkentaro/labelme/issues/465
+      pip install 'numpy<1.17'
+
       pyinstaller labelme.spec
       dist/labelme --version
     fi