Support TextMeshProUGUI for v2.0.0

[Rijicho]

Supports TextMeshProUGUI component on UGUI canvas.

If the source TMP_Text is TextMeshProUGUI,

• Replace Transform components on proxy GameObjects (and their parent) with RectTransform components
• Use canvas-space position instead of world position for ProxyTransform's Position property

Also added example scenes for TextMeshProUGUI.