MPA

A signifiant change is required in the handling logic of instruments files.
In a nutshell, we will invert the behavior of instruments and instruments presets files.
Previously, presets were hidden datas, while instruments were visible.
In the new version it should be the opposite.

1. Definitions:
Throughout this task description, the following files types will be mentioned:

Instruments:
Refers to .sound files used in the sampler 

Presets:
Actually refers to "instruments presets" which are .moodp files and are currently linked to an instrument file.

2. Previous implementation:
Until now the logic of handling instruments and presets files was as follow:

• Only instruments are visible in both the MPA and sampler browsers 
• Instruments are downloaded together with the bundled presets 
• In the sampler, instruments files needs to be loaded first so that the user can access and load the presets files 

3. New logic:

As mentioned above, we will now invert this behavior for more flexibility.
The wished behavior is:

• Only presets files are displayed in the MPA and sampler browsers.
• Instruments files become invisible and are only assets files for the presets 
• Instruments files are downloaded when downloading one of the bundled presets files 
• Presets files can be loaded directly in the sampler browser.

For the new logic, some points are to consider:

3.1 Downloads:
When download a preset file, the related instruments file is downloaded.
This occurs only if the instrument file is not already present on the user's machine.
This means for example that if 5 presets are linked to an instrument file, the instrument file is downloaded only when the user downloads one of the presets.

The presets are downloaded individually, meaning that the user can download the presets linked to an instrument file independently (doesn't need to download all the instruments presets at once) 

3.2 Previews:
In both the MPA and sampler browsers, the audio previews for the presets should be displayed for each preset.
Presets audio previews should already be supported by the system, it is now a matter of displaying the preview for each preset correctly.

3.5 sound items features:
Presets should now inherit the features of regular sound items, including:

• rate
• favorite 
• popularity note 
• add to collection/pack 
• add/edit tags 

NOTE: 
Instruments presets should be tagged as "Instruments" in the sound library and not as presets.
This means that like .sound files, the instruments presets are appearing as instruments files and not as plugin presets files.


3.4 Deleting presets: