Merge branch 't/decoder_fixes'

	97dbfe wmadec: Only decode one superframe at a time.
	d6e017 flacdec: Only process a single flac audio frame.
	1e1968 flacdec_close(): Be liberal in what you accept.
	3f96f9 oggdec: Fix EOF handling on repositioning.
	c7e2f7 oggdec: Realloc buffer to save memory.
	634e75 oggdec: Do not decode more than necessary.

These changes are well tested and there are no known problems.