Implementing inverse trigonometric and angle utility functions in NumPy

[czgdp1807]

Links to get started

See #959 (comment)

What you have to do?

• arcsin - Implement arcsin and arccos in Numpy. #1054
• arccos - Implement arcsin and arccos in Numpy. #1054
• arctan - Implement arctan, degrees, radians in Numpy. #1062
• degrees - Implement arctan, degrees, radians in Numpy. #1062
• radians - Implement arctan, degrees, radians in Numpy. #1062

[czgdp1807]

@redbopo Feel free to take it over whenever you have time.