ca'oi VUhU experimental cmavo

binary operator: complex number from argument and phase, (r, \phi) \mapsto r ei \phi

For example, re ca'oi pai is −2, and pa ca'oi vei paife'ivo is about 0.7071 + 0.7071i.

In notes:

ca'omcu
x1 is a complex number with argument x2 and phase x3