Merge pull request #9 from kattni/driver-lint-update

Update to travis.yaml and to resolve travis ci build failure

Author: dhalbert

.travis.yml

@@ -22,7 +22,7 @@ deploy:
     tags: true
 
 install:
-  - pip install pylint circuitpython-travis-build-tools
+  - pip install pylint circuitpython-build-tools
 
 script:
   - pylint adafruit_tsl2561.py

adafruit_tsl2561.py

@@ -183,7 +183,8 @@ def _read_register(self, reg, count=1):
         if count == 1:
             return self.buf[1]
         elif count == 2:
-            return (self.buf[1], self.buf[2])
+            return self.buf[1], self.buf[2]
+        return None
 
     def _write_control_register(self, reg):
         self.buf[0] = _COMMAND_BIT | _REGISTER_CONTROL