An encoder and decoder for the format described in RFC 3284:  "The
VCDIFF Generic Differencing and Compression Data Format." The encoding
strategy is largely based on Bentley-McIlroy 99:  "Data Compression
Using Long Common Strings." A library with a simple API is included,
as well as a command-line executable that can apply the encoder and
decoder to source, target, and delta files.  A slight variation from
the draft standard is defined to allow chunk-by-chunk decoding when
only a partial delta file window is available.