flac : Fix handling of raw input option.
flac : Fix handling of raw input option.

FLAC was silently ignoring options for raw input for encoding mode (but
prints an error and aborts when _de_coding).

This can lead to bug reports such as https://sourceforge.net/p/flac/bugs/389/

FLAC now prints a message about options misuse for encoding mode.

Help messages were also updated.

Patch-from: lvqcl <eea571d36fd4ab6d1b7846011ee3606fc46f6b58@gmail.com>

waitman/flac,waitman/flac,waitman/flac,waitman/flac,waitman/flac