Update README.md

Add "callouts" section.
fix(error-handling): ensure authHeaders are updated, even on errored responses, provided the headers exist
response should be rejected regardless of filter by this point
cleanup
Merge pull request #48 from booleanbetrayal/master

fix(error-handling): ensure authHeaders are updated on error responses if token headers are provided
add tests for lynndylanhurley/devise_token_auth#46
Update README.md
references #45
v0.0.24-beta1
Merge branch 'master' of https://github.com/lynndylanhurley/ng-token-auth
mods explained
Merge pull request #54 from dyaa/master

mods explained
merge