Handle multiple resolutions in most demos

This makes demos render correctly on hiDPI displays,
while also demonstrating how to handle multiple resolutions.

The 3D in 2D demo now uses "3D No-Effects" for the 3D viewport,
which is faster to render. Thanks to this, 4× MSAA is now enabled
for a better result.

The background loading demo now uses mipmaps for better-looking images.

The material testers demo now samples mouse input in a
resolution-independent manner when panning.

Default clear colors were also changed in some projects for visual
consistency with the project's theme.

2d/navigation/character.png.import

@@ -3,6 +3,9 @@
 importer="texture"
 type="StreamTexture"
 path="res://.import/character.png-7a996d3b758d22c506b76a7c15391284.stex"
+metadata={
+"vram_texture": false
+}
 
 [deps]
 

2d/navigation/icon.png.import

@@ -3,6 +3,9 @@
 importer="texture"
 type="StreamTexture"
 path="res://.import/icon.png-487276ed1e3a0c39cad0279d744ee560.stex"
+metadata={
+"vram_texture": false
+}
 
 [deps]
 

2d/navigation/level.tscn

@@ -24,3 +24,7 @@ position = Vector2( 228.464, 132.594 )
 scale = Vector2( 0.5, 0.5 )
 texture = ExtResource( 3 )
 offset = Vector2( 0, -26 )
+
+[node name="Camera2D" type="Camera2D" parent="."]
+offset = Vector2( 400, 300 )
+current = true

2d/navigation/map.png.import

@@ -3,6 +3,9 @@
 importer="texture"
 type="StreamTexture"
 path="res://.import/map.png-9eea34967fae34f4388f4a32a16da936.stex"
+metadata={
+"vram_texture": false
+}
 
 [deps]
 

2d/navigation/navigation.gd

@@ -31,12 +31,12 @@ func move_along_path(distance):
 	var last_point = $Character.position
 	while path.size():
 		var distance_between_points = last_point.distance_to(path[0])
-		
+
 		# the position to move to falls between two points
 		if distance <= distance_between_points:
 			$Character.position = last_point.linear_interpolate(path[0], distance / distance_between_points)
 			return
-		
+
 		# the position is past the end of the segment
 		distance -= distance_between_points
 		last_point = path[0]

2d/navigation/project.godot

@@ -22,6 +22,8 @@ config/icon="res://icon.png"
 [display]
 
 window/size/width=800
+window/stretch/mode="2d"
+window/stretch/aspect="expand"
 stretch/aspect="keep"
 stretch/mode="2d"
 
@@ -36,3 +38,7 @@ click={
 "events": [ Object(InputEventMouseButton,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"button_mask":0,"position":Vector2( 0, 0 ),"global_position":Vector2( 0, 0 ),"factor":1.0,"button_index":1,"pressed":false,"doubleclick":false,"script":null)
  ]
 }
+
+[rendering]
+
+environment/default_clear_color=Color( 0.160784, 0.172549, 0.278431, 1 )