V: Regression: arithmetic assignment ops on unsuitable types should give error

[SleepyRoy]

V version:
latest master - 0.1.26 a6100be (with mingw64)

OS:
win10

What did you do?
Test some arithmetic assignment ops on unsuitable types, e.g. bool += bool.

What did you expect to see?
Give an error.

What did you see instead?
No error.

NB In V1 only the following are allowed.

1. +=, -=, *=, /= on two numeric types (and += on two strings as an exception)
2. %=, <<=, >>=, &=, |=, ^= on two integer types

[medvednikov]

Fixed:

bool types only have the following operators defined: `==`, `!=`, `||`, and `&&`

Still need to do a couple of other checks.