Create blocks to customize screen layout

Added blocks to allow setting position and size of dialogs:

It is possible to configure text windows and menus separately;
It is possible to set the x and y coordinates of the dialogs;
It is possible to set the width and height of the dialogs;
It is possible to set those informations in characters or in percentage;
When a negative value is informed to the x coordinate, it is understood as "count the position from the right, instead of the left";
When a negative value is informed to the y coordinate, it is understood as "count the position from the bottom, instead of the top".

haroldo-ok / BlocklyVN8bit