Feature/Support for Whistle fingering

[eduardomourar]

This is the implementation for #9 and it depends on Fiati font v0.301

[jgadsden]

Hello @eduardomourar - generally looking excellent, thankyou, but with one bug that is easily fixed. This is an edge case, but when more than one whistle staff is included in the score then the D Tin Whistle Staff will use whatever 'transpose' is currently set - which is '0' initially, but if a staff for a tin whistle has already been processed with a 'transpose' value different to 0 (say 2 for a C Tin Whistle) then the D Tin Whistle staff fingering will use this 'transpose' value instead of the correct value of '0'.

Suggest that the if statement from line 386 of fingeringdiagram.qml could explicitly set 'transpose' for D tin whistles.

To test this, construct MuseScore score with 3 staves in order 'D Tin Whistle', 'C Tin Whistle' and 'D Tin Whistle'. Apply fingeringdiagram.qml plugin and observe first two staves are correct, but 3rd staff has C tuning not the expected D tuning.
Alternatively this can be observed when using plugin for the score https://github.com/jgadsden/tin-whistle-tablature/tree/master/examples/tin_whistle_test.mscz