Add gulp-plumber for handling errors
Merge branch 'develop'
Change name
Add test content and animation
Support size animation
Toggle open and close pocket
Polish design
Support open, close and toggle functions
Minor changes
Implement static variables in global
Support x, y, w and h attributes
Change x align to right
Support alignX and alignY attributes
Change opacity between close and open
Support moving pocket
Fix issues on Firefox
Add back cover to dim document body
Refactor code
Minor changes
Change default size