Added documentation

src/Blocks/ClearMetaOnDrop.h

@@ -1,6 +1,12 @@
 
 #pragma once
 
+// mixin for use to clear meta values when the block is converted to a pickup
+
+// Usage: inherit from this class, passing the parent class as the parameter Base
+// For example to use in class Foo which should inherit Bar use 
+// class Foo : public cClearMetaOnDrop<Bar>;
+
 template<class Base>
 class cClearMetaOnDrop : public Base
 {