Implement ATTiny85 Timer/Counter1

[Thomascountz]

I'd like to gauge if there's interest in implementing the timer. It seems like all the registers and vectors are defined, but the functionality hasn't been implemented. I don't have enough domain knowledge to understand how this would be done, but if anyone has any ideas to share to get me started, I can take a crack at it.

[haaanz]

upvote for timer1 implementation, it blocks tiny servo library from working