Merge branch '0.2.0-development'

* 0.2.0-development:
  Remove Basic Auth support
  Outsource errors to errors.go
  Add custom errors
  Return error on >= 400 status codes
Add installation info, better examples
Update errors, return ErrorUnknown on request fail
Change code so it passes go-lint
Run go fmt
Update travis notification settings
Add goveralls
Add Coverage badge
Add examples to README.md
Fix small bug in example
Add license note
Bump version
Merge branch '0.2.1-development'

* 0.2.1-development:
  Bump version
  Add license note
  Fix small bug in example
  Add examples to README.md
  Add Coverage badge
  Add goveralls
  Update travis notification settings
  Run go fmt
  Change code so it passes go-lint
  Update errors, return ErrorUnknown on request fail
  Add installation info, better examples