v2.0.10

Changelog:

• refactoring part of the code structure
• fixed page number buttons incomplete in front and rear pages
• add .d.ts file
• change sass library from node-sass to sass
• add some unit test items
• remove node-sass build script from CircleCI pipeline

v2.0.9

Changelog:

• Refactor internal processing structure
• Change css pre-processors format from SCSS to SASS
• Add German language, the language key is de