Added bodyEncoding documentation
Update README.md
Fixed bodyEncoding doc

According to #71
Fixed bodyEncoders docs

Due #71 comments
Filename param will be transferred only if it exists in file data object
Fixed codestyle for bodyEncoders (according to #66)
Removed console.log from body_encoders test
Codestyle update for bodyEncoder
Merge pull request #71 from wayx/1.0-dev

Added bodyEncoding doc