Add Strikethrough Property

Add Strikethrough Property

Add Strikethrough Property to TextEditor, TextField and TextLabel
Add InputStrikethrough Property to TextEditor and  TextField
The strikethrough map contains the following keys:

| %Property Name       | Type     | Required | Description                                                                                                        |
|----------------------|----------|----------|--------------------------------------------------------------------------------------------------------------------|
| enable               | BOOLEAN  | No       | True to enable the strikethrough or false to disable (the default value is false)                                  |
| color                | VECTOR4  | No       | The color of the strikethrough (the default value is Color::BLACK)                                                 |
| height               | FLOAT    | No       | The height of the strikethrough (the default value is 0)

Change-Id: I3098a64aba95f4b795c3307852e8aea766445c64