AIDA user requirements and wish list:
-------------------------------------

 o Don't change the Interfaces with every release.

 o Define release policy and software process

 o Histograms have a pointer to their Factory
   - used for projections and slicing (to be added) 
     forwarding to the factory
   - increment (adding another IHistogram to *this)
   - adding other IHistogram and returning new
   - other arithmetic operations

 o Create namespace AIDA (v.3)

 o AIDA binding to Python
   - __string__() to be meaningful for users (nbin, ...)
   - including user-convenience methods transforming
     from/to Python native types. Ad hoc "examples":
     
     class ITree :
     	 def __init__ (self) :
     	   ...
     	 def findH1D(self, path):
     	   ...
     
     class IHistogram1D :
     	 def toPyList(self):
     	   x = []
     	   y = []
     	   ...
     	   return x, y, ex, ey
     
     h1d.binHeight(i)
     h1d.binHeights()[i]

     h1d.label()
     ((( h1d.label   using __getattr__  ???? )))

     [mean, rms, ..., x, y, ex, ey] = h1dToPy(IHistogram1D hist)

 o Discriminate between Histograms (statistics) and
   Vectors of Points (and convert from IHist to VoP,
   not vice versa)

 o To create Objects without management, Factories 
   can be created without management (Tree)

 o "Easier" for user to create Objects without explicit
   referencing to Factories

 o Define developer level interfaces to allow mixing
   of implementations

 o HistogramFactory has a pointer to a "creational" 
   Factory (which may also deal with the management 
   (in an expt. specific way)
   - used for the histo-operational methods

 o Tree: (global) state (cwd) is bad.

 o simplicity for users, while preserve flexibility
   on the implementation ("hbook(10,"foo",50,0,50) 
   for users, IHistoFactory for developers)

 o