add conj() and arctan2()

[matthiasdiener]

No description provided.

[matthiasdiener]

arctan2 has some mypy errors, not sure what to do about them.

$ ./run-mypy.sh
pytato/array.py:1594: error: Argument 2 to "greater" has incompatible type "int"; expected "Union[Array, Union[Number, bool_, bool]]"
pytato/array.py:1594: error: Unsupported operand types for * ("int" and "Number")
pytato/array.py:1594: note: Right operand is of type "Union[Array, Union[Number, bool_, bool]]"
pytato/array.py:1594: error: Argument 2 to "where" has incompatible type "Union[Array, int, signedinteger[Any]]"; expected "Union[Array, Number, bool_, bool, None]"
pytato/array.py:1594: error: Argument 3 to "where" has incompatible type "float"; expected "Union[Array, Number, bool_, bool, None]"
Found 4 errors in 1 file (checked 13 source files)

Apart from this, it seems to work, and this PR is ready for review @inducer @kaushikcfd .

[matthiasdiener]

Ready for review, after some (ahem) convincing of Mypy.

[kaushikcfd]

Some minor feedback, otherwise LGTM, thank you!

Also needs some tests.

[inducer]

LGTM. @kaushikcfd?

[kaushikcfd]

LGTM from my end as well. Thanks @matthiasdiener!