Merge `steemauth` into `steemjs`

package.json

src/auth/index.js

src/auth/protocol/operations.js

src/auth/protocol/serializer.js

src/auth/protocol/signature.js

src/auth/protocol/signature/ecdsa.js

src/auth/protocol/signature/ecsignature.js

src/auth/protocol/signature/enforce-types.js

src/auth/protocol/signature/hash.js

src/auth/protocol/types/chain-types.js

src/auth/protocol/types/fast-parser.js

src/auth/protocol/types/index.js

src/auth/protocol/types/key-private.js

src/auth/protocol/types/key-public.js

src/browser.js