Doxygen: Update relevant @since tags to 0.5.1.

src/input/input.c

@@ -538,7 +538,7 @@ SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in)
  * useful when an application did not create the input stream by specifying
  * an input module, but instead some shortcut or convenience wrapper did.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API const struct sr_input_module *sr_input_module_get(const struct sr_input *in)
 {

src/log.c

@@ -170,7 +170,7 @@ SR_API int sr_log_callback_set_default(void)
  *
  * @return SR_OK upon success.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API int sr_log_callback_get(sr_log_callback *cb, void **cb_data)
 {

src/resource.c

@@ -42,7 +42,7 @@
  *
  * @return List of strings that must be freed after use, including the strings.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API GSList *sr_resourcepaths_get(int res_type)
 {

src/strutil.c

@@ -281,7 +281,7 @@ SR_PRIV int sr_atof_ascii(const char *str, float *ret)
  * @return On success, the number of characters that would have been written,
  *         not counting the terminating NUL character.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API int sr_sprintf_ascii(char *buf, const char *format, ...)
 {
@@ -320,7 +320,7 @@ SR_API int sr_sprintf_ascii(char *buf, const char *format, ...)
  * @return On success, the number of characters that would have been written,
  *         not counting the terminating NUL character.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API int sr_vsprintf_ascii(char *buf, const char *format, va_list args)
 {
@@ -445,7 +445,7 @@ SR_API int sr_vsprintf_ascii(char *buf, const char *format, va_list args)
  *         Notice that only when this returned value is non-negative and less
  *         than buf_size, the string has been completely written.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API int sr_snprintf_ascii(char *buf, size_t buf_size,
 	const char *format, ...)
@@ -492,7 +492,7 @@ SR_API int sr_snprintf_ascii(char *buf, size_t buf_size,
  *         Notice that only when this returned value is non-negative and less
  *         than buf_size, the string has been completely written.
  *
- * @since 0.6.0
+ * @since 0.5.1
  */
 SR_API int sr_vsnprintf_ascii(char *buf, size_t buf_size,
 	const char *format, va_list args)