Courtesy of Paul's NeoPixel code, discovered the teensy's DWT_CYCCNT - switch the clockless code over to using that, should fix clockless code on the teensy 3.1 and complete teensy 3.1 code for us.
Update README.md

Adding note about folder name
Fixed port definitions for ATtiny45
Fix compile errors for avr
Merge pull request #37 from tobiasebsen/attiny45

Fixed port definitions for ATtiny45
sync w/master
mergining in updates from 2.1 branch