added communication protocols doc
s3 links for finished images
Made all diagrams PNG

Touch up of I2C and SPI graphics
Added captions to all images
Added code examples to each protocol
Wording changes
Added diy module tutorial doc.
Finished creating links and added Resource section
Changed out image assets to s3 host
a great number of minor edits
editorial changes
replaced dropbox links with s3 links
added in links to comms protocols document
Merge pull request #59 from tessel/DIY-module

DIY module guide and communication protocols doc