Ignore text insertion cursor when previewing markdown (stevencohn#1460)

stevencohn#1416

OneMore/Models/PageEditor.cs

@@ -154,6 +154,15 @@ public async Task<XElement> ExtractSelectedContent()
 					(AllContent || e.Attributes().Any(a => a.Name == "selected" && a.Value == "all")))
 				.ToList();
 
+			if (runs.Any() && AllContent)
+			{
+				// filter out the blank cursor to avoid inadvertently inserting a newline
+				runs = runs.Except(runs.Where(e =>
+					e.Attributes().Any(a => a.Name == "selected" && a.Value == "all") &&
+					e.GetCData().Value == string.Empty))
+					.ToList();
+			}
+
 			// no selections found in body
 			if (!runs.Any())
 			{

OneMore/Models/PageReader.cs

@@ -103,6 +103,11 @@ public string GetSelectedText(bool withTitle = true)
 		/// <returns></returns>
 		public string ReadTextFrom(IEnumerable<XElement> paragraphs, bool allText)
 		{
+			if (!paragraphs.Any())
+			{
+				return string.Empty;
+			}
+
 			var builder = new StringBuilder();
 
 			foreach (var paragraph in paragraphs)