Implement baselineShift and verticalAlign (preferred).

Transverse Box Alignment, specifies how an inline-level box is aligned within the line, and by how much the box is shifted up from its alignment point.
 https://drafts.csswg.org/css-inline/#propdef-vertical-align
 https://www.w3.org/TR/css-inline-3/#propdef-baseline-shift
 https://www.w3.org/TR/css-inline-3/#transverse-alignment

lib/extract/extractText.js

@@ -94,6 +94,8 @@ export default function(props, container) {
         dx,
         dy,
         alignmentBaseline,
+        baselineShift,
+        verticalAlign,
     } = props;
     let {
         rotate,
@@ -137,5 +139,7 @@ export default function(props, container) {
         deltaX,
         deltaY,
         alignmentBaseline,
+        baselineShift,
+        verticalAlign,
     };
 }