In the functions Compress and Strdup allocate 20 additional characters

more than the strlen of the original string to cope with some situations like
vector<vector<T>> (note the missing blank between the >>)

In the section generating code for STL, replace generated lines like
  if (!R__n) return;
by
  if (R__n) {
..
  }
With this change, the generated code works also when the option "+"
is not specified in the pragma of LinkDef


git-svn-id: http://root.cern.ch/svn/root/trunk@5965 27541ba8-7e3a-0410-8455-c3a389f83636