add refs page (branches and tags)

quite some code is added, this will be cleaned up in a following code iteration.

- make sure to free some more allocated git objects.
- use fputs() asmuch as possible instead of fprintf().
- code cleanup

TODO

@@ -4,6 +4,7 @@ performance:
 
 layout:
 - make top menu look nicer in links/lynx again.
+- show tags in log.
 
 documentation:
 - improve mandoc pages.