Correct the error handling in TInterpreter::Execute(...,TObjArray*)

The issues at http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=16769
was actually about not handling correctly defaulted parameters
and not about the 'this pointer'.

In addition LastIndex for a TObjArray is not as reliable as for
TList to get the number of entries in the collection (i.e. it
was wrong to use it here).
Fix test using vrepm_d (noticed by unused variable warning)
Test moved to roottest/root/tree/reader.
Remove help for CINT binaries that are long gone.
Add note on N::B<N::A> name change; add PPC64; update planned feature set.
Update (c) year.
Shorter var names; indentation.
Fix the NULL return check in HandleEnumDecl.
Turn opt off completely until llvm bug / stressGraphics is fixed.
From Benedikt: AddFriendToClass(); and me: cleanup fwd decls.
  Remove bad fclose() calls introduced in e5b0b42b

  These fclose calls were added by mistake during a code cleanup during port to
  xrootd 3.3.x . The bug is fatal when authentication is enabled and affects all
  5.34 versions 5.34/06 to 5.34/09 .
Revert no-optimization for JIT; we need it until the CodeGen bug is understood!

This reverts commit 8f85c529125ca622ec95dbc3ed92ead815dc555d.