Scroll sync, iOS fix, webworker

1. File Manager

• User can now view the Features list from https://sashimi-note.herokuapp.com/features
• Fixed iOS double click not begin registered. #391
• Fixed iPhone SE / iPhone 5 layout not being displayed properly #391
• Added nudging on rename text field when there is an error #396

2. Content

• Added a basic scroll sync support for all view mode (Slides, Pages, HTML) #393
• Wrap markdown-it parsing and rendering into a web worker thread. #377
  Markdown parsing will not hung up the UI anymore.
• Enhance performance of rendering diagrams slightly #388

3. Database

1. Adding of default features.md text on first creation
2. Fixed rename of folder path
3. DateTime is changed to long format

---

Sashimi Note v0.1.5 marks the final release for NUS CS3284.