Stable release compatible with Processing 4.0.

Reorganized the project structure to make it more standardized and to facilitate debugging/development (see this section in the wiki for details).

It also fixes the following issues since the last release of the mode:

• App examples would be easier to use in Android Studio, and should not crash: #611
• Fixed the automatic SDK installation issues: #756

Note: Download the pdex file to install the mode manually.