change params order of Insert* functions for glist; improve gstr.IsNumber

.example/container/glist/basic.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+	"github.com/gogf/gf/container/glist"
+)
+
+func main() {
+	l := glist.New()
+	// Push
+	l.PushBack(1)
+	l.PushBack(2)
+	e0 := l.PushFront(0)
+	// Insert
+	l.InsertBefore(e0, -1)
+	l.InsertAfter(e0, "a")
+	fmt.Println(l)
+	// Pop
+	fmt.Println(l.PopFront())
+	fmt.Println(l.PopBack())
+	fmt.Println(l)
+}