KeepTogether in paragraph broken with more than one chunk and different font

[kunkelt]

The fix of #271 and commit 1d3c049 brought a new issue for our application. Paragraphs with more than one chunk and different fonts lead to unexpected line breaks inside a paragraph.

Code to reproduce:

public class TestBad134 {
	public static final String CREATED_PDF = "./src/test/TestBad134.pdf";

	public static void main(String[] args) {
		Document document = new Document();
		try {
			PdfWriter.getInstance(document, new FileOutputStream(CREATED_PDF));
			document.open();

			Chunk chunk1 = new Chunk("Hier ", FontFactory.getFont(BaseFont.COURIER, 10));
			Chunk chunk2 = new Chunk("fetter", FontFactory.getFont(BaseFont.COURIER_BOLD, 10));
			Chunk chunk3 = new Chunk(" Text", FontFactory.getFont(BaseFont.COURIER, 10));

			Paragraph para = new Paragraph();
			para.add(chunk1);
			para.add(chunk2);
			para.add(chunk3);
			para.setKeepTogether(true);
			document.add(para);
		}
		catch (DocumentException | IOException de) {
			System.err.println(de.getMessage());
		}
		document.close();
	}
}

Result is:

Expected: