Added BB Rev 1 files

Changelog: added missing traces on LEDs
TODO: fix passives silkscreens too small or on top of pads, mark LED and
tantalum polarities, enlarge P8 and P9 drills, mark TP vias on back
silk, fix silk orientation consistency, break out SPI bus, try to place
ADS1299 caps a bit closer to IC
Merge branch 'master' of https://github.com/gskelly/eeg