Add partial applicative typeclass functions

[lmbollen]

We currently have functions like .==. that can operate on Signals. However, I find myself often writing .foo. pure bar when comparing signals to constants.

With these changes(inspired by @gergoerdi's retrocomputing lib) we can write .foo bar instead.

Still TODO:

• [ ] Determine if there are more operators we'd like to add signal functions for.
• [ ] Write a changelog entry (see changelog/README.md)
• [ ] Check copyright notices are up to date in edited files