- adding the ability to change the access and refresh cookies (#58)

- adding the ability to control the secure flag of the cookie
- adding the ability to inject custom claims from the access token into the authenticated headers
- updating the readme to reflect the changes
- changed the claims option to match-claims
- changed the upstream config option to upstream-url, same as command line line
- changed the config options for keepalive, keepalive -> upstream-keepalives, same as command line
- added the headers command line option as it was missing
- updated the example config_sample.yml
- adding additional unit tests where i could