Support for Xaphoon fingering

[eduardomourar]

As discussed in skuntzmann/xaphoon_dev#4 we will be adding Xaphoon fingering to this plugin. We have the following instrument variations (as discussed here):

• Xaphoon in C
• Xaphoon in B♭
• Xaphoon in D
• Xaphoon in G

Here are the steps we will take to achieve this:

• Add these charts to the Fiati font (Add Xaphoon fingering fiati#6)
• Update spreadsheet to list basic instrument fingering
• Add Xaphoon note mapping to the plugin itself
• Test plugin and add new instrument to sample MuseScore file