document.activeElement can rarely have no 'blur' method (in Modal#open)
Merge pull request #35 from sakura-internet/hotfix/no_blur_method

Modal#open(): existing checks 'blur' method in document.activeElement.
Merge branch 'master' into gh-pages by CicleCI
Build 'flagrate.min.js' and 'flagrate.min.css'
Build API documentation