Prevent default link behavior when closing modals.

https://github.com/cferdinandi/modals/issues/12
Added fix for UMD structure

https://github.com/cferdinandi/kraken/issues/92
Merge pull request #13 from cferdinandi/umd-fix

Added fix for UMD structure
updated readme
Various changes

* Switched to Ruby Sass.
* Fixed unit test paths.
* Switched to event bubbling.
Merge pull request #14 from cferdinandi/event-bubbling

Various changes
updated gulpfile.js
Fixed event listener filter
Merge pull request #15 from cferdinandi/dev

Fixed event listener filter
Fixed commonjs bug
Merge pull request #16 from cferdinandi/development

Fixed commonjs bug
Version 6.*

* Modals now full-screen on small screens.
* Added overflow-y scrolling for all modals.
* Removed `offset` variable from script API.
* Added open/closed `state` variable.
* Added close modal support for backspace and delete keys.
Merge pull request #17 from cferdinandi/development

Version 6.*
Merge branch 'master' into gh-pages