R20170323

This is the first of "release", and uses the code from 23rd March 2017, which although it has issues, is generally stable and is in use by hundreds, and possibly thousands of users.

In future I intend for the Master HEAD to be the cutting edge with the latest fixes and enhancements, and I will create releases when the new code has been used by the community for a while to ensure stability.

I've decided to use date base release naming e.g. YYYYMMDD, because using version numbers e.g. 1.0.0 would imply that the core is fully functional and compatible with the Arduino API and IDE, and I don't know if thats ever going to be the case.