added v3 schematic

...for Digispark with integrated LiPo charger and power booster

A marriage of the following:
https://s3.amazonaws.com/digistump-resources/files/97a1bb28_DigisparkSchematic.pdf
http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/PowerCell-v13.pdf (from https://www.sparkfun.com/products/11231)