Basalt 1.7 Update

- New Objects (Flexbox, Graph, Treeview)
- Pluginsystem to add/remove functionality
- Reworked the entire Object system, instead of one big Object Class we have multiple classes: Object, VisualObject, ChangeableObject
- Instead of one big Frame Class we have multiple Frame Classes: BaseFrame, Frame, MovableFrame, ScrollableFrame, MonitorFrame, Flexbox
- Removed the Animation Object, and added a animation plugin instead
- Removed the Graphic Object and merged it's functionality with the image object
- Updated currently existing objects

docs/objects/Object/getZIndex.md

@@ -0,0 +1,22 @@
+## getZIndex
+
+### Description
+
+Returns the Z-index of the object
+
+The Z-index determines the order of overlapping objects. Objects with higher Z-index values will be displayed above objects with lower Z-index values.
+
+### Returns
+
+1. `object` The current Z-index value
+
+### Usage
+
+* Creates a default button and gets its Z-index value.
+
+```lua
+local mainFrame = basalt.createFrame()
+local aButton = mainFrame:addButton():setText("My Button")
+local zIndex = aButton:getZIndex()
+basalt.debug(zIndex) -- Prints the Z-index value
+```