Added
- Added the `__eq__` method to the `GraphemeString` object.
This is to support the `==` operator when comparing two `GraphemeString` objects.
- Added the `__add__` method to the `GraphemeString` object.
This is to support the `+` operator when adding two `GraphemeString` objects together.
- Added the `__hash__` method to the `GraphemeString` object.
This is to support the `hash()` function for a `GraphemeString` instance and allows it (as an example) to be used as
a `dict` key.