Add dynamic refresh period
Revert "Add dynamic refresh period"

This reverts commit 30c42237cceda9e89a3e0fdceda00d4ea27bf32d.
Make refresh period dynamic

Keep a reference to the timer and check at each render if the
UpdateSpeed on the IFace has changed.
Merge pull request #6 from FrenchData/DynamicRefreshPeriod

Dynamic refresh period