Cleanup a whole pile of build warnings

[j-mutter]

Currently when building BK, there are 755 warnings:

This is super noisy, and obscures potential problems, so I've gone ahead and cleaned up pretty much all of them but 2:

The vast majority were missing overrides on methods, and the rest were a bit of a mixed bag of initializer/field ordering, unused variables, unhandled values in switch statements, etc.

For the switch statements specifically, I opted to add all the missing values instead of just a default as a bit of documentation and to help searching in the future, and I tried to group them in a somewhat logical manner.

There were a couple places where accessors were being called and completely unused, so maybe those were just mistakes and the intent was to actually set a value? I left comments around those ones - they are mostly isControllableFeedbackOnly calls in some UI elements that should maybe be setControllableFeedbackOnly?

The two that I left are as follows:

1. A warning about the version of libServus that is bundled in the app. It was built against MacOS 10.15, and I am currently linking against 10.13. This is also up from 10.10 which was causing a slew of similar warnings with other packages. 10.13 is almost 10 years old at this point, so I figured increasing that was probably fine, but I wasn't sure about jumping all the way to 10.15, even though things might not work properly on older versions anyway.

2. The unused function getApp in BlinderKitten/Modules/juce_organicui/app/OrganicApplication.h. Obviously it's unused and can be removed, but it seemed like maybe something that might be needed later without having to go find/recreate it again.