Demos: ensure all use fun main() = application {

- Adjust some demo window sizes.
- Replace Random.double by Double.uniform
- Tweak some demos so screenshots look more interesting

orx-property-watchers/src/jvmDemo/kotlin/DemoPropertyWatchers01.kt

@@ -1,22 +1,20 @@
 import org.openrndr.application
 import org.openrndr.extra.propertywatchers.watchingProperty
 
-fun main() {
-    application {
-        program {
-            val state = object {
-                val x by watchingProperty(mouse::position) {
-                    it.x
-                }
-
-                val xx by watchingProperty(::x) {
-                    it * it
-                }
+fun main() = application {
+    program {
+        val state = object {
+            val x by watchingProperty(mouse::position) {
+                it.x
             }
 
-            extend {
-                state.x
+            val xx by watchingProperty(::x) {
+                it * it
             }
         }
+
+        extend {
+            state.x
+        }
     }
-}
+}