Get prefix removed from getters

True for Bus, Strip, Vban and Output types.

Bus[i].Eq() and Strip[i].Eq() now return pointers to eQ structs.
This makes it easier to extend Eq types in future if desired.

Strip[i].Comp()  now return pointer to comp struct
Strip[i].Gain() now return pointer to gain struct
This is to support the new API features in Potato 3.0.2.8

Removed casting in factory function return statements.
Since types are satisfied implicitly.

eQ struct type tests added

eq_test.go

@@ -0,0 +1,15 @@
+package voicemeeter
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetEq(t *testing.T) {
+	//t.Skip("skipping test")
+	__e := newEq("strip[0].EQ", 0)
+	t.Run("Should return an eQ type", func(t *testing.T) {
+		assert.NotNil(t, __e)
+	})
+}