Disparate char type

We do not have an actual `char` type, it is merely the textual representation of the `int8_t` type. 

If you for example wanted to propagate the character constant display type to all constants of type `char` (alias of `int8_t`) you would unknowingly make all non-char `int8_t` constants that display type.

```
>>> bv.parse_type_string("int8_t")
(<type: immutable:IntegerTypeClass 'char'>, '')
```