transonic.dataclass for numba.jitclass and cython cdef class

Created originally on Bitbucket by paugier (Pierre Augier)

from transonic import dataclass, boost

@dataclass
class MyStruc:
    attr: int
    
    def compute(self, arg: int):
        return self.attr + arg
        
    def modify(self, arg: int):
        self.attr = arg
        
@boost
def func(o: MyStruct, a: int):
    o.modify(a)
    return o

@boost
def func1(o: MyStruct, a: int):
    return o.compute(a)

‌

See https://github.com/serge-sans-paille/pythran/issues/1116

and what is done in https://github.com/ogrisel/pygbm/blob/master/pygbm/splitting.py#L21