Still working on the widgets attribute

Can now corectly set multiple sprite to a widget
We can also chose to display a sprite in it's list or not by setting it's draw attr
Can now resize a widget, this will not move it (scale does), can also resize widget's sprite
Rearranged panels -> Created different types

Panels can now store other panels, that make them dependants (master / slave)
Made a Tabwidget, it is attached to a panel
Enhanced event system and conception