Feature/pre compiled eval scripts (#658)

* Added support of pre-compiled eval expressions

* Added unit tests for eval.Function

* Added RemoteType and RemoteObjectType enums

* Refactored function generation

* Refactored Document and Element loading logic

* Removed redundant fields from cdp.Page

* Exposed eval.Runtime to external callers

* Added new eval.RemoteValue interface

pkg/drivers/cdp/eval/helpers_test.go

@@ -1,20 +1 @@
 package eval
-
-import (
-	. "github.com/smartystreets/goconvey/convey"
-	"testing"
-)
-
-func TestWrapExp(t *testing.T) {
-	Convey("wrapExp", t, func() {
-		Convey("When a plain expression is passed", func() {
-			exp := "return true"
-			So(wrapExp(exp, 0), ShouldEqual, "() => {\n"+exp+"\n}")
-		})
-
-		Convey("When a plain expression is passed with args > 0", func() {
-			exp := "return true"
-			So(wrapExp(exp, 3), ShouldEqual, "(arg1,arg2,arg3) => {\n"+exp+"\n}")
-		})
-	})
-}