feat(tracker): add menu to load instrument presets

The presets are embedded in the executable, so there's no additional files.

Closes #91

tracker/presets/Fairies.yml

@@ -0,0 +1,43 @@
+name: Fairies
+numvoices: 1
+units:
+    - type: envelope
+      id: 1
+      parameters: {attack: 80, decay: 96, gain: 128, release: 88, stereo: 0, sustain: 80}
+    - type: envelope
+      id: 2
+      parameters: {attack: 0, decay: 96, gain: 128, release: 88, stereo: 0, sustain: 40}
+    - type: distort
+      id: 3
+      parameters: {drive: 32, stereo: 0}
+    - type: send
+      id: 5
+      parameters: {amount: 96, port: 0, sendpop: 1, target: 12}
+    - type: oscillator
+      id: 232
+      parameters: {color: 3, detune: 56, gain: 64, lfo: 0, phase: 3, shape: 64, stereo: 0, transpose: 64, type: 1}
+    - type: oscillator
+      id: 233
+      parameters: {color: 3, detune: 72, gain: 64, lfo: 0, phase: 3, shape: 64, stereo: 0, transpose: 64, type: 1}
+    - type: addp
+      id: 234
+      parameters: {stereo: 0}
+    - type: distort
+      id: 10
+      parameters: {drive: 96, stereo: 0}
+    - type: filter
+      id: 12
+      parameters: {bandpass: 0, frequency: 16, highpass: 1, lowpass: 0, negbandpass: 0, neghighpass: 0, resonance: 24, stereo: 0}
+    - type: mulp
+      id: 13
+      parameters: {stereo: 0}
+    - type: pan
+      id: 14
+      parameters: {panning: 64, stereo: 0}
+    - type: delay
+      id: 15
+      parameters: {damp: 64, dry: 128, feedback: 64, notetracking: 2, pregain: 96, stereo: 1}
+      varargs: [48, 24]
+    - type: outaux
+      id: 19
+      parameters: {auxgain: 64, outgain: 64, stereo: 1}