Add Remove & Merge Lists

[PrzemyslawKlys]

This PR resolves issue:

• Add ability to merge & remove lists #206

This PR adds:

• Merging document.Lists[0].Merge(document.Lists[1]);
• Removal document.Lists[0].Remove();

How to use:

internal static void Example_BasicLists3(string folderPath, bool openWord) {
    string filePath = System.IO.Path.Combine(folderPath, "Document with Lists3.docx");
    using (WordDocument document = WordDocument.Create(filePath)) {
        var paragraph = document.AddParagraph("This is 1st list");
        paragraph.ParagraphAlignment = JustificationValues.Center;

        WordList wordList1 = document.AddList(WordListStyle.Headings111);
        wordList1.AddItem("Text 1 - List1");
        wordList1.AddItem("Text 2 - List1", 1);
        wordList1.AddItem("Text 3 - List1", 2);

        paragraph = document.AddParagraph("This is 2nd list");
        paragraph.ParagraphAlignment = JustificationValues.Center;

        WordList wordList2 = document.AddList(WordListStyle.Headings111);
        wordList2.AddItem("Text 1");
        wordList2.AddItem("Text 2", 1);
        wordList2.AddItem("Text 3", 2);

        paragraph = document.AddParagraph("This is 3rd list").SetColor(Color.DeepPink).SetUnderline(UnderlineValues.Double);
        paragraph.ParagraphAlignment = JustificationValues.Center;

        WordList wordList3 = document.AddList(WordListStyle.Bulleted);
        wordList3.AddItem("Text 7.1", 1);
        wordList3.AddItem("Text 7.2", 2);
        wordList3.AddItem("Text 7.3", 2);
        wordList3.AddItem("Text 7.4", 0);
        wordList3.AddItem("Text 7.5", 0);
        wordList3.AddItem("Text 7.6", 1);
        wordList3.AddItem("Text 7");

        paragraph = document.AddParagraph("This is 4th list").SetColor(Color.Aqua).SetUnderline(UnderlineValues.Double);
        paragraph.ParagraphAlignment = JustificationValues.Center;

        WordList wordList4 = document.AddList(WordListStyle.Bulleted);
        wordList4.AddItem("Text 8");
        wordList4.AddItem("Text 8.1", 1);
        wordList4.AddItem("Text 8.2", 2);
        wordList4.AddItem("Text 8.3", 2);
        wordList4.AddItem("Text 8.4", 0);
        wordList4.AddItem("Text 8.5", 0);
        wordList4.AddItem("Text 8.6", 1);

        Console.WriteLine("List count: " + document.Lists.Count); // "List count: 4

        document.Lists[0].Remove();

        Console.WriteLine("List count: " + document.Lists.Count); // "List count: 3

        document.Lists[0].Merge(document.Lists[1]);

        Console.WriteLine("List count: " + document.Lists.Count); // "List count: 2

        document.Save(openWord);
    }
}