Merge pull request #3 from jasondreyzehner/master

Update README.md with capitalization info
Merge pull request #4 from jasondreyzehner/master

add ai and eps formats
Merge pull request #5 from jasondreyzehner/master

add greyscale options
Merge pull request #10 from jasondreyzehner/master

add avatars
Merge branch 'master' of github.com:bitpay/bitpay-brand