implement string hashes for unordered_map used by libc++ in OSX 10.9.

Fixes Cintex and Reflex.
replace a couple of string by std::string (solve a build failure on cygwin)
 o RooAbsPdf

   - In chi2FitTo() orward Extended() command to createChi2()
tmpnam() is deprecated on OSX 10.9. Suppress warnings in CINT.
tmpnam() is deprecated on OSX 10.9. Suppress warnings in CINT.
Make protocol 'xroot:' equivalent to 'root:'

Signed-off-by: Fons Rademakers <Fons.Rademakers@cern.ch>
on OSX 10.9 suppress atos deprecation warning by using the -d option.
make version v5-34-11.
Close the file before starting to free TFile's resources
Fix math core fit tests
Remove a print statement