fix small screen issue

[thecuvii]

Description

In small screen, quality is bad. So I double render and effect size to get better quality.
also need #225

Specific Changes proposed

1. add doubleSizeForSmallScreen function in utils.js, if currentWidth is small than videoWidth, double currentWidth and currentHeight.
2. change render and effect size in plugin.js init function.
3. change size in plugin.js handleResize_ function

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Unit Tests updated or fixed
  • Docs/guides updated
• Reviewed by Two Core Contributors