Feature: Implement EKI at level_0.

Feature: Implement EKI at level_0.

This provides the initial eki implementation and unit testing.

I had to choose between making an f_eki compliment of f_iki or appending EKI into f_iki.
I ended up choosing the latter because it is simpler and will require fewer cross-dependencies when using higher levels.
There is enough overlap in functionality to justify this.
These are almost completely identical specifications.

Add additional unit tests to catch more problems and implement these same unit tests in f_iki for consistency purposes.

This includes some code clean up.
The `wrapped` is changed to use `0x0` and `0x1` rather than `F_false` and `F_true`.
These are functionally identical but the code is more consistent when having `0x0`, `0x1`, and `0x2` instead of `F_false`, `F_true`, and `0x2`.