Add function to generate toy MC from a Decay3Body. It requires c++0x.
Implementation of the algorithm to generate toys from a pdf expression.
        It requires the generate function to be implemented in all the
        models used in the expression.
Preliminary implementation of the generate function for a Gaussian. Still
        needs to take into account limits.
Prepare the makefile to use the c++0x implementation.
Make the example gaussian fit generate toy events if requested.
Define one single random engine that all models have to use.
Define a virtual default generate function for models that only throws an
        exception. Models have to override it with their specific implementation.
Add functions to evaluate the inverse of the erf function.
Add generate function for the Crystal Ball model.
Add test of the Crystal Ball generation and fit.
Add generate function for the exponential model.
Add test of the exponential generation and fit.
Add generate function for the double Crystal Ball model.
Add test of the double Crystal Ball generation and fit.
Add the implementation of the inverse of the complemented imcomplete gamma
        integral, necessary for the generation with an Argus distribution.