Bugfix, optimization

• Fixed all bugs connected with common pin change
• Refresh method optimized

First release

Features

• asynchronous display refresh
• user specified refresh rate (+/- 3Hz)
• user specified number of displays
• support different common pins ( cathode / anode )
• display strings, negative or positive integer or floats
• support for most latin characters ( excluding K, M, V, W, X, Z )