Get rid of `True` in characteristic (rules, output and json) as it is
implicit. This way, the same syntax is used for characteristic as for
the rest of the features.
Co-authored-by: William Ballenthin <william.ballenthin@fireeye.com>
The `Element` class is just used for testing. By using `Element` we are
not testing the actual code. Also, every time we implement a new feature
for the `Feature` class, we need to implement it for `Element` as well.
Replace `Element` by `Integer`.
