Issue457: Fractional Scaling on Windows

[ptorngren]

Add support for FPAPI: Add new class SwingUtils with methods for leveraging the FPAPI

Modify concerned classes and methods to call SwingUtils and use Rectangle2D and float/double variables instead of Rectangle and integers:

• DefaultTokenPainter.paintBackground()
• RSyntaxUtilities.getLineWidthUpTo()
• SyntaxView: tabBase, tabSize, clipStart, clipEnd, .calculateLongestLine(), lineToRect(), damageLineRange(), modelToView(), nextTabStop(), paint()
• Token.listOffsetToView()
• TokenImpl: getListOffset(), getWidthUpTo(), listOffsetToView()
• VisibleWhitespaceTokenPainter()
• WrappedSyntaxView.modelToView()

Layout/painter changes:

• SyntaxViiew.nextTabStop(): Add offset for tabs to avoid losing tabs that occur on the same pixel as the preceding character end
• ConfigurableCaret: use Rectangle2D and floats/doubles, primarily to avoid double lines on thick vertical line style
• Add RSyntaxTextArea.onGraphicsChange() to let owner refresh font metrics when graphic properties change
• DefaultTokenPainter: Fix tab lines by offsetting the line location slightly
• SwingUtils.drawChars(): Use TextLayout for very long lines or containing complex characters (inspired by SwingUtilities2)

Adapt to Java 11: Replace calls to deprecated elements with corresponding elements for Java 9 or later Rectangles and bounds:

• add SwingUtils.getBounds() to wrap calls to modelToView2D(pos).getBounds() in a null-safe way
• replace calls to JTextComponent.modelToView(int pos) with calls to SwingUtils.getBounds(JTextComponent c, int pos)
• replace calls to JTextComponent.viewToModel(Point p) with calls to JTextComponent.viewToModel2D(Point2D p)

Events:

• replace calls to InputEvent.getModifiers() with calls to MouseEvent.getModifiersEx()
• replace calls to Toolkit.getMenuShortcutKeyMask() Toolkit.getMenuShortcutKeyMaskEx()
• replace references to Event.META_MASK with InputEvent.META_DOWN_MASK
• replace references to Event.CTRL_MASK with InputEvent.CTRL_DOWN_MASK
• replace references to MouseEvent.BUTTON1_MASK with MouseEvent.BUTTON1_DOWN_MASK Not modified:
• SyntaxScheme calls deprecated XMLReaderFactory.createXMLReader() which should be replaced with SaxParserFactory

Also modified the Demo Root Pane:

• add a text example
• show a larger screen centered on monitor
• add a font selector
• add menu option to make whitespace visible