cmd/geth, jsre: restore command line editing on windows

PR #856 broke command line editing by wrapping stdout with a filter that
interprets ANSI escape sequences to fix colored printing on windows.
Implement the printer in Go instead so it can do its own
platform-dependent coloring.

As a nice side effect, the JS console is now noticeably more responsive
when printing results.

Fixes #1608
Fixes #1612

jsre/jsre.go

@@ -65,7 +65,6 @@ func New(assetPath string) *JSRE {
 	}
 	re.loopWg.Add(1)
 	go re.runEventLoop()
-	re.Compile("pp.js", pp_js) // load prettyprint func definition
 	re.Set("loadScript", re.loadScript)
 	return re
 }
@@ -255,35 +254,19 @@ func (self *JSRE) loadScript(call otto.FunctionCall) otto.Value {
 	return otto.TrueValue()
 }
 
-// PrettyPrint writes v to standard output.
-func (self *JSRE) PrettyPrint(v interface{}) (val otto.Value, err error) {
-	var method otto.Value
+// EvalAndPrettyPrint evaluates code and pretty prints the result to
+// standard output.
+func (self *JSRE) EvalAndPrettyPrint(code string) (err error) {
 	self.do(func(vm *otto.Otto) {
-		val, err = vm.ToValue(v)
+		var val otto.Value
+		val, err = vm.Run(code)
 		if err != nil {
 			return
 		}
-		method, err = vm.Get("prettyPrint")
-		if err != nil {
-			return
-		}
-		val, err = method.Call(method, val)
+		prettyPrint(vm, val)
+		fmt.Println()
 	})
-	return val, err
-}
-
-// Eval evaluates JS function and returns result in a pretty printed string format.
-func (self *JSRE) Eval(code string) (s string, err error) {
-	var val otto.Value
-	val, err = self.Run(code)
-	if err != nil {
-		return
-	}
-	val, err = self.PrettyPrint(val)
-	if err != nil {
-		return
-	}
-	return fmt.Sprintf("%v", val), nil
+	return err
 }
 
 // Compile compiles and then runs a piece of JS code.