Small additions and new patches!

[reaby]

Adds peak volume to vu metter and change color to red when audio clips.
Changed build-in presets to support subfolders.
Added new presets and removed some not-so-great sounding ones, tried to gain-stage the presets.

[vsariola]

Thanks!

I see these are three separate things, so please rewrite git history to make them into three separate pull requests / commits, so I can review them more easily & merge them one by one. I don't have time to test these tonight, but I already have some questions:

1. Changing to red is a good idea. But there was already the line indicating peak volume, what was wrong with that?
2. This seems like a good idea; I need to check the implementation.
3. The presets are mostly the old 4klang presets. I'm ok with adjusting the gains, but I'm not quite sure about deleting presets (almost all snares are gone). While you are chasing great sound, some of these may have come about because they are very little bytes, so it's not always just about the sound. Also, I see lots of renaming of the presets; I'd like to have such minor tweaking in a separate commit.

The presets adjustment could be pull request with four commits. For example: first commit renaming all existing presets into better names; second commit adding new presets; third commit tweaking the gains; and fourth commit deleting the presets that you think are bad. These commits are in the order of agreeableness: I might agree the merge the first three, but not the fourth. Having them in four clean commits helps the review process.

[vsariola]

Any chance of cleaning up this pull request? I might look into it to get the gain staged instruments, but that "79 files changed" is a bit intimidating, without more context.