Turn off buffering to not return cached data when reading.
Turn off buffering to not return cached data when reading.

Fixes issue #67

rhempel/ev3dev-lang-python,ensonic/ev3dev-lang-python,ensonic/ev3dev-lang-python-1,dwalton76/ev3dev-lang-python,dwalton76/ev3dev-lang-python,ddemidov/ev3dev-lang-python-1