feat(tracker/presets): new and tweaked presets from Reaby

The presets are also organized by their type into subfolders.

Closes #136

tracker/presets/LEAD/BellLead2.yml

@@ -0,0 +1,28 @@
+name: LEAD BellLead2
+numvoices: 4
+units:
+    - type: envelope
+      id: 163
+      parameters: {attack: 34, decay: 81, gain: 68, release: 78, stereo: 0, sustain: 103}
+    - type: oscillator
+      id: 165
+      parameters: {color: 97, detune: 70, gain: 31, lfo: 0, phase: 0, shape: 86, stereo: 0, transpose: 76, type: 2, unison: 2}
+    - type: oscillator
+      id: 1002
+      parameters: {color: 72, detune: 69, gain: 64, looplength: 821, loopstart: 2374, phase: 0, samplestart: 557335, shape: 103, stereo: 0, transpose: 67, type: 4, unison: 1}
+    - type: addp
+      id: 166
+      parameters: {stereo: 0}
+    - type: mulp
+      id: 167
+      parameters: {stereo: 0}
+    - type: pan
+      id: 168
+      parameters: {panning: 59, stereo: 0}
+    - type: delay
+      id: 169
+      parameters: {damp: 12, dry: 103, feedback: 84, notetracking: 0, pregain: 69, stereo: 1}
+      varargs: [12550, 24402, 21265, 32419]
+    - type: outaux
+      id: 172
+      parameters: {auxgain: 12, outgain: 29, stereo: 1}