Settings Screen and first 2 settings (#18)

* white sleep screen

* quicker pwr button

* no extra spacing between paragraphs

* Added settings class with de/serialization and whiteSleepScreen setting to control inverting the sleep screen

* Added Settings screen for real, made settings a global singleton

* Added setting for extra paragraph spacing.

* fixed typo

* Rework after feedback

* Fixed type from bool to uint8

src/screens/SleepScreen.cpp

@@ -4,6 +4,7 @@
 
 #include "config.h"
 #include "images/CrossLarge.h"
+#include "CrossPointSettings.h"
 
 void SleepScreen::onEnter() {
   const auto pageWidth = GfxRenderer::getScreenWidth();
@@ -13,6 +14,11 @@ void SleepScreen::onEnter() {
   renderer.drawImage(CrossLarge, (pageWidth - 128) / 2, (pageHeight - 128) / 2, 128, 128);
   renderer.drawCenteredText(UI_FONT_ID, pageHeight / 2 + 70, "CrossPoint", true, BOLD);
   renderer.drawCenteredText(SMALL_FONT_ID, pageHeight / 2 + 95, "SLEEPING");
-  renderer.invertScreen();
+
+  // Apply white screen if enabled in settings
+  if (!SETTINGS.whiteSleepScreen) {
+    renderer.invertScreen();
+  }
+
   renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
 }