feat: Customisable floor buttons

fgd/bases/BasePortButton.fgd

@@ -7,6 +7,7 @@
 		0 : "Solid"
 		1 : "Non-Solid"
 		]
+	filtername(filterclass) : "Filter Name" : : "A filter entity that restricts which things can press the button. If set, the builtin filtering is disabled."
 
 	// Inputs
 	input PressIn(void) : "Activate the button as if it was pressed, sending it to the bottom position."
@@ -15,4 +16,6 @@
 	// Outputs
 	output OnPressed(void) : "Called when the button has been pressed."
 	output OnUnPressed(void) : "Called when the button has been released."
+	output OnPressedPlayer[engine](void) : "Called when the button is pressed by a player - useless on cube/sphere buttons."
+	output OnPressedCube(void) : "Called when the button is pressed by a cube (specifically a non-player)."
 	]

fgd/point/prop/prop_floor_button.fgd

@@ -12,6 +12,7 @@
 		]
 
 	// Outputs
+	output OnPressedPlayer(void) : "Called when the button has been pressed by any player."
 	output OnPressedBlue(void) : "Called in Coop when the button has been pressed by ATLAS."
 	output OnPressedOrange(void) : "Called in Coop when the button has been pressed by P-Body."
 	]

fgd/point/prop/prop_under_floor_button.fgd

@@ -8,6 +8,7 @@
 	model(studio) : "Button model" : "models/props_underground/underground_floor_button.mdl" : "The model to be used in game"
 
 	// Outputs
+	output OnPressedPlayer(void) : "Called when the button has been pressed by any player."
 	output OnPressedBlue(void) : "Called in Coop when the button has been pressed by ATLAS."
 	output OnPressedOrange(void) : "Called in Coop when the button has been pressed by P-Body."
 	]