Merge pull request #72 from julsam/master

Add attributes to make Text selectable & mouseEnabled
Enable mouse wheel on Tabs to scroll them
Progress & Slider now allow negatives values #73
Merge pull request #75 from julsam/tabwheelscroll

[Feature] Enable mouse wheel on Tabs to scroll them
Merge pull request #76 from julsam/negativeProgress

Progress & Slider now allow negatives values #73