all: remove unused functions from includes

Signed-off-by: Mahyar Koshkouei <mk@deltabeard.com>

include/sid.h

@@ -1,44 +1,4 @@
 #include <stdint.h>
 #include "playback.h"
 
-/**
- * Set decoder parameters for SID.
- *
- * \param	decoder Structure to store parameters.
- */
 void setSid(struct decoder_fn* decoder);
-
-/**
- * Initialise SID playback.
- *
- * \param	file	Location of SID file to play.
- * \return			0 on success, else failure.
- */
-int initSid(const char* file);
-
-/**
- * Get sampling rate of SID file.
- *
- * \return	Sampling rate.
- */
-uint32_t rateSid(void);
-
-/**
- * Get number of channels of SID file.
- *
- * \return	Number of channels for opened file.
- */
-uint8_t channelSid(void);
-
-/**
- * Read part of open SID file.
- *
- * \param buffer	Output.
- * \return			Samples read for each channel.
- */
-uint64_t readSid(void* buffer);
-
-/**
- * Free SID file.
- */
-void exitSid(void);