v0.4.2

Release notes

• minor bug fixes and updates
• Includes:* [image classifier] Fixes memory leak / dispose of processed image #680 by @joeyklee
• fix single quote typo in nn reference #679 by @vndrewlee
• [neural net fix] Merges neural net fix in release to development branch #676 by @joeyklee
• get networks batchSize and epochs from config.training #674 by @TobiasNickel
• [docs] begins adding utils documentation #670 by @joeyklee
• [devops] adds script to update docs ml5 versions #666 by @joeyklee
• UNET and BodyPix Segmentation result handling #664 by joeyklee
• Adding index_test.js for UNET #659 by EonYang
• Fixes memory leaks in #684