Remove most warnings in ORX

Closes #61

orx-panel/src/main/kotlin/org/openrndr/panel/elements/Slider.kt

@@ -167,10 +167,8 @@ class Slider : Element(ElementType("slider")) {
             if (it.key == KEY_ENTER) {
                 try {
                     val number = NumberFormat.getInstance().parse(keyboardInput).toDouble()
-                    if (number != null) {
-                        interactiveValue = number.coerceIn(range.min, range.max)
-                    }
-                } catch (e : ParseException) {
+                    interactiveValue = number.coerceIn(range.min, range.max)
+                } catch (e: ParseException) {
                     // -- silently (but safely) ignore the exception
                 }
                 keyboardInput = ""

orx-panel/src/main/kotlin/org/openrndr/panel/elements/TextElements.kt

@@ -81,9 +81,6 @@ abstract class TextElement(et: ElementType) : Element(et) {
 }
 
 fun TextElement.bind(property: KMutableProperty0<String>) {
-    var currentValue: Double? = null
-
-
     if (root() as? Body == null) {
         throw RuntimeException("no body")
     }

orx-panel/src/main/kotlin/org/openrndr/panel/style/Matcher.kt

@@ -48,6 +48,9 @@ class Matcher {
                 Combinator.LATER_SIBLING -> if (result == MatchingResult.RESTART_FROM_CLOSEST_DESCENDANT) {
                     return result
                 }
+                Combinator.DESCENDANT -> {
+                    // intentionally do nothing
+                }
             }
         }
     }