Added base64 support for key and value output fmt

[Donis-]

Tested only with visual studio compiler/windows.
Base64 implementation taken based on results from https://github.com/gaspardpetit/base64

[edenhill]

Thank you for your contribution!

The base64 implementation is dual licensed, some old Apache license (less of a problem), and an Apple license that is troublesome.

See if you can find a 2 or 3-claused BSD license implementation of base64 instead.

[Donis-]

I was skeptical about the Apple part. Before i integrate, is this one acceptable:
http://web.mit.edu/freebsd/head/contrib/wpa/src/utils/base64.c

License under :
http://web.mit.edu/freebsd/head/contrib/wpa/
3 claused?

[jjlin]

I was skeptical about the Apple part. Before i integrate, is this one acceptable:
http://web.mit.edu/freebsd/head/contrib/wpa/src/utils/base64.c

License under :
http://web.mit.edu/freebsd/head/contrib/wpa/
3 claused?

@Donis- Any near-term plans to continue with integrating the Jouni Malinen base64 implementation? If not, do you mind if I take it up?