Release v2.3.0

Installation image, md5sum, and installation guide:

• https://s3.amazonaws.com/berrynet/images/berrynet-2.3.0.img
• https://s3.amazonaws.com/berrynet/images/berrynet-2.3.0.md5sum
• https://github.com/DT42/BerryNet/wiki/Installation

Features and Improvements

1. Provide installation image.
2. Fix node-opencv building issue.
3. Fix BerryNet repository enablement issue.

Incompatible Changes

N/A