Improve boolean handling

In library there is this code:

   def set_ignore_implicit_angular_wait(self, ignore):
        if not is_boolean(ignore):
            raise TypeError("Ignore must be

But it might be better to use Robot Framework or SeleniumLibrary is_truthy method to improve boolean handling. SeleniumLibrary method is in here: https://github.com/robotframework/SeleniumLibrary/blob/master/src/SeleniumLibrary/utils/types.py
And it has been there since 3.0 release.

SeleniumLibrary boolean handling is explained in here: http://robotframework.org/SeleniumLibrary/SeleniumLibrary.html#Boolean%20arguments

I can provide you a pull request to fix the problem. Should I copy paste the implementation or can I use method from the SeleniumLibrary? If I can, it will raise minimum required SeleniumLibrary to 3.0.

Start with the set_ignore_implicit_angular_wait method shown in the issue, then read SeleniumLibrary's types.py and its boolean-argument documentation. Confirm the supported boolean values and whether the project can use SeleniumLibrary 3.0; done means this setting accepts the intended boolean forms and rejects invalid values consistently.