API design change on MajVjCoordinateHelper

Assume three requirements.

1. Give a position by X and Y at a position in a window
2. Give a position by normalized position -1 to 1 for X and Y, and it represents an address in an regular square that longer sides fit the window
3. Give a position by normalized position -1 to 1 for X and Y, and it represents an address in an regular square that shorter sides fit the window
Abandon MajVjCoordinateHelper.

We may want to have rage parameters in 2D API.
Stop importing unused java.nio.FloatBuffer in Example4.java
Add 2D APIs
Add strokeWeight() to the 2D API
Add fill() to the 2D API
Add ellipse() to the 2D API
Add alpha blending and line functions to avoid using GLES20 directly from MajVj2DImpl.