Improve textboxes to allow multiple Runs/Paragraphs **Breaking Changes**

[PrzemyslawKlys]

This PR solves:

• Issue with Text Replacement in Multi-Line Text Boxes #224

There are Breaking Changes:

• Removed Text property
• Removed WordParagraph property
• Added Paragraphs property, allowing for full manipulation

var textBox = document.AddTextBox("[Grab your reader’s attention with a great quote from the document or use this space to emphasize a key point. To place this text box anywhere on the page, just drag it.]");

Console.WriteLine("TextBox Text: " + textBox.Paragraphs[0].Text);

textBox.Paragraphs[0].Text = "We can then modify the text box text";

Console.WriteLine("TextBox Text: " + textBox.Paragraphs[0].Text);

Console.WriteLine("TextBoc Color: " + textBox.Paragraphs[0].Color.ToString());

textBox.Paragraphs[0].Text = "This is a text box 1";

Console.WriteLine("TextBox Text: " + textBox.Paragraphs[0].Text);