- improve 1D root finder and minimization classes

  - return a bool in method RootFinder::Solve and IMinimizer1D::Minimize
   to be consistent with the other numerical algo. classes
   Classes in MathCore were also returning the wrong values (status=1 instead of zero)

  - add Status() method to check the validity of the cached values

  - change default tolerance to 10-8 (abs) and 10^-10 (values which were used as default in the Mathcore Brent)

  - return a bool also in SetFunction

- Mathcore Brent classes: 

   - pass tolerances and max iterations to the Brent methods. So do not use anymore the hard coded values
   - add possibility also to pass Npx (number of points to use in the grid for the bracketing search) and max number 
     of iterations (before was hard coded to 10)
    

This changes uses suggestion reported by https://savannah.cern.ch/bugs/index.php?61242


git-svn-id: http://root.cern.ch/svn/root/trunk@32583 27541ba8-7e3a-0410-8455-c3a389f83636