Refactor method names
Reformat
Extract default settings to constructor
Reformat code for use min() and max()
Remove is-dragged class not only on leftControl
Add hack for right render control with initial value
Remove excess curlybrace
Add keyCode
Begin key binding function, add valueByControl method
Complete left and right control moving by keys
Use render functions on drag instead of simple dragging
Refactor RangeControl to use validate value method on all setters
Use validation of value in leftValue and rightValue functions