Symbol index preferences

[abusalimov]

This changes the way symbols and meta items are shown in the Ctrl+R list:

Code sections:

### Pragma mark section #############################
=== Banner comment section ==========================

Indexed symbols:

 ⒡  function_name ( ) ; — function declaration
—Ⓕ– function_name ( ) { … } — function
 Ⓜ  macro_name … — macro object
—Ⓜ– macro_name ( ) … — macro function
 ⒞  type_name ; — type declaration
—Ⓒ– type_name { … } ; — type
 Ⓣ  name_t ; — typedef

Task tags:

  ✎  NOTE no need to optimize this logic
  ✅  REVIEW needed
  ✔  TODO pretty print the output
 ǃǃ✔  FIXME remove this shit ASAP

Contains #28 and #29, do not merge!