Implemented analogWriteResolution()
Fixed constrain() algorithm
Expanded pinData struct size
Added doxygen comments for surrounding functions
Add analogWriteResolution() functional test to tests folder
Make assignment operator private (inaccessible) for HardwareSerial class.
Merge pull request #56 from zfields/analogWriteResolution

Implemented analogWriteResolution()
Merge pull request #62 from zfields/hardwareSerialW4

Make assignment operator private (inaccessible) for HardwareSerial class...