complex-numbers: exponential of complex number (#1095)
complex-numbers: exponential of complex number (#1095)

* complex-numbers: exponential of complex number

For some reason, there was no test for exp(a + bi) where a != 0 and b != 0. This PR adds such a test with exact values that are simple to define (requiring no rounded values).

Proof:
```
e^(ln(2) + PI * i) = e^ln(2) * e^(PI * i) = 2 * e^(PI * i)
e^(PI * i) = cos(PI) + isin(PI) = -1 + 0i = -1
e^(ln(2) + PI * i) = 2 * e^(PI * i) = 2 * -1 = -2
```

* bump version to 1.3.0

* adopt new schema

* Fix incorrect sign for expected value

ErikSchierboom/x-common,exercism/x-common,petertseng/x-common,jmluy/x-common,jmluy/x-common,petertseng/x-common,rpottsoh/x-common,rpottsoh/x-common,exercism/x-common,jmluy/x-common,ErikSchierboom/x-common