Performance enhancements

This commit:
* Updates the README to include an example for correct documentation
generation
* Converts the interactive Terminal into an Executable (from Runnable),
giving better control over the runtime.
* Updates the Renderer and Mixer with a higher performance function to
append Transforms.
* Adds the new #+() (alias: #add()) method to Transform, returning a new
component which combines the non-boundary properties of the base
Transform and another (use #add!() to perform this internally).