Distinguish between VSTi and VST-FX

Nobody has claimed this yet.

This is a placeholder to distinguish the difference between a VST Instrument and a VST Effects programatically.

This distinction will have the following benefits:
- DLLs that aren't VeSTige compatible can be filtered from certain file views
- Effects browser can filter out non-FX related DLLs
- Instrument browser can filter out non-Instrument related DLLs

Since this has been discussed already, I'll quote the more educated on the topic...

> @grejppi wrote:
> The VST specification does not provide any means to distinguish between instruments and effects.
> Not sure if gig and sf2 belong in the same category as LADSPA and VST which are executable binaries. GIG and SF2 are sample banks; plain ol' data so to say. You wouldn't move the existing `samples/` folder to `plugins/audiofileprocessor/`, would you?

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> @curlymorphic responded:
>
> > The VST specification does not provide any means to distinguish between instruments and effects.
>
> This can be deduced from the input / outputs.

Start by reviewing the issue discussion and the quoted VST specification constraint, then examine how input and output capabilities might distinguish instruments from effects. Done means the project can reliably separate VST instruments and effects so the relevant plugin and browser views can filter them.

Written by the indexing model from the issue text.