Add numpy types on type system

[guilhermeleobas]

The following code fails:

@rjit('double(double, double)')
    def logaddexp(x, y):
        return np.logaddexp(x, y)

x = np.log(1e-50)
y = np.log(2.5e-50)
logaddexp(x, y)

...
rbc/tests/test_numpy_rjit.py:50:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
rbc/remotejit.py:261: in __call__
    atypes = tuple(Type.fromvalue(a, target_info) for a in arguments)
rbc/remotejit.py:261: in <genexpr>
    atypes = tuple(Type.fromvalue(a, target_info) for a in arguments)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

cls = <class 'rbc.typesystem.Type'>, obj = -115.12925464970229, target_info = <rbc.targetinfo.TargetInfo object at 0x10c5766d0>

    @classmethod
    def fromvalue(cls, obj, target_info):
        """Return Type instance that corresponds to given Python value.
        """
        n = _python_imap.get(type(obj))
        print(type(obj))
        if n is not None:
            return cls.fromstring(n, target_info)
>       raise NotImplementedError('%s.fromvalue(%r)'
                                  % (cls.__name__, obj))
E       NotImplementedError: Type.fromvalue(-115.12925464970229)

rbc/typesystem.py:751: NotImplementedError

x and y have types numpy.float64.

[pearu]

See #39 (comment)