Add third party base64 encode/decode functions obtained from
    <https://github.com/ReneNyffenegger/development_misc>.
Base64 encode message data in web interface output.
Fix recently introduced bug in discard reporting code: discards
    were being written instead of possible duplicate messages.

	modified:   src/bruce/web_request_handler.cc
	new file:   src/third_party/base64/base64.cpp
	new file:   src/third_party/base64/base64.h
	new file:   src/third_party/base64/readme.txt
	new file:   src/third_party/base64/test.cpp