manual reformat stuff
renamed CreateIndividual -> New
idea for improvement
added keys() and __len__ to EvaluationContext
* all kwargs are moved to args (before it was until the first missing one) by using their default value
* unknown kwargs are allowed if the function argspec has a "varkw" variable (eg **kwargs)
fixed "size=None" handling in NumpyRandom base class: now, we need to look for it in args, not kwargs as before
fixed uniform() signature
workaround nan(min|max) not supporting some arguments

They only support a subset of the arguments of min and max. Since we use a single signature function for both, I created wrappers for nanxxx which have accept the extra arguments but raise an exception if they are actually used (if they are passed a value that is different from the default value)
fixed the case where "**kwargs" is in no_eval
switched new() to use FunctionExpr and allow new() for the whole population (no filter, nor number)