add support for floating drawings

- added need elements and test for them

src/file/drawing/text-wrap/text-wrapping.ts

@@ -0,0 +1,22 @@
+// http://officeopenxml.com/drwPicFloating-textWrap.php
+import { Distance } from "../drawing";
+
+export enum TextWrapStyle {
+    NONE,
+    SQUARE,
+    TIGHT,
+    TOP_AND_BOTTOM,
+}
+
+export enum WrapTextOption {
+    BOTH_SIDES = "bothSides",
+    LEFT = "left",
+    RIGHT = "right",
+    LARGEST = "largest",
+}
+
+export interface TextWrapping {
+    textWrapStyle: TextWrapStyle;
+    wrapTextOption?: WrapTextOption;
+    distanceFromText?: Distance;
+}