* Shorten now refuses to input data from or output data to a tty.
* Fixed crash when trying to create seek tables from a non-shorten file.
* -s and -S options can now create seek table files from data read on stdin.
* Seek tables are now appended to non-stdout output file when reading
uncompressed data from stdin.
Shorten reduces the size of waveform files (such as audio) using
Huffman coding of prediction residuals and optional additional
quantisation. It supports lossless and lossy modes.
