Move to SDK EInkDisplay and enable anti-aliased 2-bit text (#5)

* First pass at moving to SDK EInkDisplay library

* Add 2-bit grayscale text and anti-aliased rendering of text

* Render status bar for empty chapters

* Refresh screen every 15 pages to avoid ghosting

* Simplify boot and sleep screens

* Give FileSelectionScreen task more stack memory

* Move text around slightly on Boot and Sleep screens

* Re-use existing buffer and write to whole screen for 'partial update'

src/screens/BootLogoScreen.cpp

@@ -11,4 +11,9 @@ void BootLogoScreen::onEnter() {
   renderer.clearScreen();
   // Location for images is from top right in landscape orientation
   renderer.drawImage(CrossLarge, (pageHeight - 128) / 2, (pageWidth - 128) / 2, 128, 128);
+  const int width = renderer.getUiTextWidth("CrossPoint", BOLD);
+  renderer.drawUiText((pageWidth - width)/ 2, pageHeight / 2 + 70, "CrossPoint", true, BOLD);
+  const int bootingWidth = renderer.getSmallTextWidth("BOOTING");
+  renderer.drawSmallText((pageWidth - bootingWidth) / 2, pageHeight / 2 + 95, "BOOTING");
+  renderer.flushDisplay();
 }