Merge changes from str_substitution that are unrelated to that branch.

Included is a small bugfix to an ast_str helper, but most of these changes
are simply doxygen fixes.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@185912 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/tdd.c

@@ -274,7 +274,9 @@ static inline float tdd_getcarrier(float *cr, float *ci, int bit)
 	PUT_TDD_STOP;	/* Stop bit */ \
 } while(0);	
 
-/*! Generate TDD hold tone */
+/*! Generate TDD hold tone
+ * \param buf Result buffer
+ * \todo How big should this be??? */
 int tdd_gen_holdtone(unsigned char *buf)
 {
 	int bytes = 0;