Update old (and wrong) parts of callgrind documentation.

Update old (and wrong) parts of callgrind documentation.
This obviously was already wrong in 3.2.x :-(

* Old --fn-recursion=... / --fn-caller=... options are called
  --separate-recs=... / --separate-callers=... since quite some
  time for consistency with e.g. --separate-threads=yes.
  Error noted from bug 153335.
* Function specifications support wildcards since quite some time;
  specification of a prefix only does not work, but the full
  function has to match. This was needed to allow to specify 'foo'
  without also specifying 'foo1'.
* The script 'callgrind' does not exist since merging into
  valgrind.
* Rename callgrind from being a 'heavyweight' to a 'call graph'
  profiler, similar to the description in the quick start overview.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@7272