Ultima supports constructor (partially)

[vorj]

Ultima in this PR supports member functions.
And the ultima also supports constructors partially.

[jenkins-maekawa]

Test (commit 9b9fbc1) passed in vega.

[jenkins-maekawa]

Test (commit 9b9fbc1) passed in titanv.

[vorj]

@LWisteria please review it.

I found many bugs...

[jenkins-maekawa]

Test (commit c5dadd8) passed in titanv.

[jenkins-maekawa]

Test (commit c5dadd8) passed in vega.

[vorj]

@LWisteria OK, it's ready to review.

[LWisteria]

Please describe why this PR is needed and what this PR is fixing.

[vorj]

@LWisteria
For now, we are trying to support clpy.core.fusion .
However, when we tried to use fused clpy.core.min (, max , argmin , argmax , nanmin , and nanmax ), current ClPy caused UltimaRuntimeError because current clpy.core.fuse depends on implicit conversion on generated C++ codes.
The functions uses struct min_max_st_T , which is just a C structure, but on original CuPy it was template<typename T> struct min_max_st<T> , which has (non-explicit) constructor from double value (it means that CuPy's min_max_st<T> can be constructed from double value implicitly ).

I think that the behavior of current fuse that it depends on implicit conversion is the exactly the problem.
However, current CuPy doesn't have the problematic codes, so we shouldn't fix the fuse implementation codes directly ( because the codes will be thrown away when we update CuPy base version(#33)).

In these reasons, I proposed partially constructor emulation on ultima.
The member function support is just additional implementation (it shares almost all codes with constructor implementation).

[LWisteria]

The member function support is just additional implementation

YAGNI. Fewer functions are better to reduce bugs. Please remove it.

And you need test to check implicit conversion constructor.

[jenkins-maekawa]

Test (commit 5de0af3) passed in vega.

[jenkins-maekawa]

Test (commit 5de0af3) passed in titanv.

[vorj]

@LWisteria I fixed it. Please review it.

[LWisteria]

Please fix PR title and descriptions

[jenkins-maekawa]

Test (commit 5b4720b) passed in titanv.

[jenkins-maekawa]

Test (commit 5b4720b) passed in vega.

[vorj]

@LWisteria I did it. Please review it.

[LWisteria]

LGTM