File upload / download and Basic / Bearer authentication support added

[tahiralmas]

This pull request will introduce following new features in RestServer.

• For JWT support, bearer header support added.
• For role based permissions, authentication process separated into 'authenticate' and 'authorize' methods
• File upload and download without using multipart/form-data

[tyzoid]

Thanks - I haven't had a chance to review this in its entirity, but this looks good so far! Thanks for the help. I'm planning on completing the review sometime later today or early tomorrow.