o RooAbsReal

     - Add interface to specify hint for plot sampling binning. This is useful
       for p.d.f.s shapes such as un-interpolated histogram p.d.f.s that may
       not correctly converge on a good projection curve using the default
       recursive division strategy without an initial hint on where to sample.

   o RooHistPdf,RooHistFunc

     - Implement plotSamplingHints() method that suggests to same just before
       and just after each bin boundary


   o RooProdPdf

     - Forward plotSamplingHint() from relevant component p.d.f.s


   o RooAddPdf

     - Implement plotSamplingHints() that forwards hints of component p.d.f.s
       and merges them if necessary


   o RooRealIntegral

     - Forward plotSamplingHint() from integrand
    

   o RooAbsFunc

     - Define plotSamplingHints() interface


   o RooRealBinding

     - Implement plotSamplingHints() method that forwards hints from bound RooAbsReal


   o RooScaledFunc

     - Implement plotSamplingHints() method that forwards hints from bound RooAbsFunc


   o RooCurve

     - Use plot sampling hints define by input function to perform initial sampling
       if provided, otherwise fall back to default strategy of frame binning sampling.


   o RooBanner

     - Upgrade version tag to 2.90


   o RooCintUtils

     - Adjustment in CINT include file location


git-svn-id: http://root.cern.ch/svn/root/trunk@25209 27541ba8-7e3a-0410-8455-c3a389f83636