Allow direct use of images

Delta	27 lines added, 8 lines removed, 19-line increase

CREDITS.md

		* Mikael Grev: [MigLayout](http://www.miglayout.com/)
		* Tom Eugelink: [MigPane](https://github.com/mikaelgrev/miglayout/blob/master/javafx/src/main/java/org/tbee/javafx/scene/layout/fxml/MigPane.java)
		-* Vladimir Schneider: [flexmark](https://github.com/vsch/flexmark-java)
		* Jens Deters: [FontAwesomeFX](https://bitbucket.org/Jerady/fontawesomefx)
		-* Shy Shalom, Kohei Taketa: [juniversalchardet](https://github.com/takscape/juniversalchardet)
		+* Dieter Holz, [PreferencesFX](https://github.com/dlsc-software-consulting-gmbh/PreferencesFX)
		* David Croft, [File Preferences](http://www.davidc.net/programming/java/java-preferences-using-file-backing-store)
		* Alex Bertram, [Renjin](https://www.renjin.org/)
		+* Vladimir Schneider: [flexmark](https://github.com/vsch/flexmark-java)
		* Michael Kay, [XSLT Processor](http://www.saxonica.com/)
		+* Shy Shalom, Kohei Taketa: [juniversalchardet](https://github.com/takscape/juniversalchardet)

src/main/java/com/scrivenvar/preview/HTMLPreviewPane.java

		@Override
		public void componentResized( final ComponentEvent e ) {
		- // Scaling a bit below the full width prevents the horizontal scrollbar
		- // from appearing.
		- final int width = (int) (e.getComponent().getWidth() * .95);
		- HTMLPreviewPane.this.mImageLoader.widthProperty().set( width );
		+ setWidth( e );
		}

		@Override
		- public void componentMoved( final ComponentEvent e ) {
		+ public void componentShown( final ComponentEvent e ) {
		+ setWidth( e );
		}

		@Override
		- public void componentShown( final ComponentEvent e ) {
		+ public void componentMoved( final ComponentEvent e ) {
		}

		@Override
		public void componentHidden( final ComponentEvent e ) {
		+ }
		+
		+ /**
		+ * Sets the width of the {@link HTMLPreviewPane} so that images can be
		+ * scaled to fit. The scale factor is adjusted a bit below the full width
		+ * to prevent the horizontal scrollbar from appearing.
		+ *
		+ * @param e The component that defines the image scaling width.
		+ */
		+ private void setWidth( final ComponentEvent e ) {
		+ final int width = (int) (e.getComponent().getWidth() * .95);
		+ HTMLPreviewPane.this.mImageLoader.widthProperty().set( width );
		}
		}

src/main/java/com/scrivenvar/processors/markdown/ImageLinkExtension.java


		try {
		+ // If the direct file name exists, then use it directly.
		+ if( Path.of( url ).toFile().exists() ) {
		+ return link.withStatus( LinkStatus.VALID ).withUrl( url );
		+ }
		+ } catch( final Exception ignored ) {
		+ }
		+
		+ try {
		final Path imagePrefix = getImagePrefix().toPath();