Merge pull request #20 from agudulin/bugfix

Refactor canvas module a bit
Fixed tools buttons abstraction
Added animation on button hover
Added modals class
Added modals stylesheets
Added "about" modal window
Added client code for "about" modal
Merge pull request #21 from agudulin/modals

Added Modals class and boilerplate "About" modal
Update js files
Merge branch 'master' into bugfix
Some fixes

* Changed author name
* Fixed modal button position