minor cleanups ...

- use for loops instead of while loops for basic list traversals
- only calculate word length one time in CLI complete functions
- use calloc instead of malloc + memset
- remove some unnecessary casts
- formatting tweaks 


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@7618 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/pbx.h

@@ -626,7 +626,7 @@ int ast_parseable_goto(struct ast_channel *chan, const char *goto_string);
 int ast_explicit_goto(struct ast_channel *chan, const char *context, const char *exten, int priority);
 int ast_async_goto_if_exists(struct ast_channel *chan, const char *context, const char *exten, int priority);
 
-struct ast_custom_function* ast_custom_function_find(char *name);
+struct ast_custom_function* ast_custom_function_find(const char *name);
 int ast_custom_function_unregister(struct ast_custom_function *acf);
 int ast_custom_function_register(struct ast_custom_function *acf);