WL#3526: Incremental BASE64 encoding/decoding

Affects: Server-Prototype Only   —   Status: Un-Assigned   —   Priority: Medium


The current set of functions for performing BASE64 encoding cannot handle
incremental encodings, i.e., encoding the data piecemeal. Instead you have to
accumulate the data into one big buffer in memory, and then encode it all in one
go. This works well for small chunks of data, but if huge amounts of data are to
be encoded, an incremental approach is necessary.


Implement an incremental, stream-oriented, encoder/decoder that can write
to/read from an IO_CACHE.