Abstracting I/O Pins

Introducing abstract I/O pins (binary and analog). Preparing move of
GPIO, SPI and I2C connections to a new Raspberry.IO nuget.
Merged pull request #9
Renamed I*Pin into I*BinaryPins
Merged neutmute-master to PinAbstraction
Updated logging nugets
Added .gtignore file to VS solution
Merge branch 'master' of github.com:raspberry-sharp/raspberry-sharp-io

Conflicts:
	Test.Gpio.Pca9685/Program.cs
	Test.Gpio.Pca9685/app.config
	Test.Gpio.Pca9685/packages.config