Improved Matlab compatibility

[ShuhuaGao]

From the documentation of MATLAB on ellipke and ellipj, we see that the inputs to these functions can also be arrays. In the current implementation, we have to use the dot syntax to broadcast if we have an array of input values. However, this broadcasting syntax will lead to an array of tuples, which differs from that of MATLAB (tuple of arrays). Thus, I try to improve MATLAB compatibility by providing methods that accept array inputs directly.

Note that this PR does not comprise backward compatibility of this package, since I only add new methods. The implementation is rather simple and has been fully tested.