Add images to word export (#22)

* Add images to word export

Create image part for a word doc, create images,
clone images between document fragments,
and track relationship IDs of images.

Export caption text. Formatting of image captions
will be handled separately.

* Cleanup word fragment writer dispose

Src/xWorks/ConfiguredLcmGenerator.cs

@@ -861,7 +861,7 @@ private static string GenerateSrcAttributeFromFilePath(ICmFile file, string subF
 			{
 				filePath = MakeSafeFilePath(file.AbsoluteInternalPath);
 			}
-			return settings.UseRelativePaths ? filePath : new Uri(filePath).ToString();
+			return filePath;
 		}
 
 		private static string GenerateSrcAttributeForMediaFromFilePath(string filename, string subFolder, GeneratorSettings settings)
@@ -1940,9 +1940,8 @@ private static IFragment GeneratePictureContent(ConfigurableDictionaryNode confi
 					contentGenerator.WriteProcessedContents(writer, settings.ContentGenerator.AddImageCaption(captionBldr.ToString()));
 				}
 				writer.Flush();
+				return bldr;
 			}
-
-			return bldr;
 		}
 
 		private static IFragment GenerateCollectionItemContent(ConfigurableDictionaryNode config, DictionaryPublicationDecorator publicationDecorator,