Add instruments.xml option

Instruments.xml option still needs work, but it's good enough for a demonstration.
Also regenerated the template in --template-mode to be compatible with 2.0.3 and gave it a rename

Author: duck57

share/instruments/instruments.xml

@@ -7033,6 +7033,34 @@
                   </Articulation>
                   <genre>orchestra</genre>
             </Instrument>
+            <Instrument id="4-hands-piano">
+                  <longName>Piano (4-hands)</longName>
+                  <shortName>4 Hnd Pno.</shortName>
+                  <description>4-handed piano part (a.k.a. 2 players and one piano)</description>
+                  <musicXMLid>keyboard.piano.4hands</musicXMLid>
+                  <staves>4</staves>
+                  <clef>G8va</clef>
+                  <bracket>1</bracket>
+                  <bracketSpan>2</bracketSpan>
+                  <barlineSpan>2</barlineSpan>
+                  <clef staff="2">G</clef>
+                  <clef staff="3">F</clef>
+                  <clef staff="4">F8vb</clef>
+                  <bracket staff="3">1</bracket>
+                  <bracketSpan staff="3">2</bracketSpan>
+                  <barlineSpan staff="3">2</barlineSpan>
+                  <aPitchRange>21-108</aPitchRange>
+                  <pPitchRange>21-108</pPitchRange>
+                  <Channel>
+                        <program value="0"/>
+                  </Channel>
+                  <Articulation>
+                        <velocity>100</velocity>
+                        <gateTime>95</gateTime>
+                  </Articulation>
+                  <genre>common</genre>
+                  <genre>orchestra</genre>
+            </Instrument>
             <Instrument id="upright-piano">
                   <longName>Upright Piano</longName>
                   <shortName>Pno.</shortName>