Improved element documentation

elements/core/doc.go

@@ -0,0 +1,7 @@
+// Package core provides tools that allow elements to easily fulfill common
+// interfaces without having to duplicate a ton of code. Each "core" is a type
+// that can be embedded into an element directly, working to fulfill a
+// particular interface. Each one comes with a corresponding core control, which
+// provides an interface for elements to exert control over the core. They
+// should be kept private.
+package core