Use the C++ API.

The "bool" type is built-in.

RTTI adds overhead to the binary, and we don't need that.

We don't use exceptions currently.  Since allowing exceptions means a
lot of overhead, this commit disables the feature.

Allows eliminating more dead code.  Adds two more C++ options that may
reduce the binary size.

Conflicts:
	src/PlaylistSave.cxx

The song's URI must be UTF-8, not filesystem character set.

Fixes minor Windows compatibility problem.

Implements Mantis feature request 3582.

Interleaving was completely wrong.  This code was never used, so it
didn't have an effect.

Works around assertion failure in decoder_timestamp().

Use av_get_sample_fmt_string() to obtain a human-readable string.

API simplification.

Implement the "scan_stream" method that can read tags from any
input_stream object.  This requires a FLAC__IOCallbacks implementation
based on the input_stream API.