Remove static from header to allow multiple instances.

Thanks to @BlinxFox!

Rewrite of entire library:

• Written to be more platform agnostic
• First examples are simplified
• DMX serial port usage is simplified
• Simplified break signal detection. Has the potential to not synchronize perfectly, but testing has shown good results
• Serial port must be started before calling begin() of this library

Thanks to @pjpmarques for help testing!

Having issues detecting startCodes. Changed to a periodic interrupt from a pin change interrupt

Some files had old licensing info, everything is now MIT

The Mark After Break was going low during it's 8 uS high time, I've removed this which should fix issues with external DMX fixtures

Initial release includes read and write functions over XLR