Misc fixes for callgrind_annotate

Misc fixes for callgrind_annotate

* Patch from bug 198649 (callgrind_annotate doesn't cumulate counters)
  When there were multiple call sites in one line, the aggregated
  call count/cost numbers in the source annotation were wrong
* Callgrind often produces absolute file names.
  Make it work with relative file names requested for annotation from
  the command lines.
* More in sync with parser in KCachegrind: make summary line optional.
  We can also use the "totals:" line for this.
* Count of numbers in summary can be smaller then number of events given

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@10777