Remove unused imports

src/MusicSheetAPI.ts

@@ -1,4 +1,3 @@
-import Vex = require("vexflow");
 import {IXmlElement} from "./Common/FileIO/Xml";
 import {VexFlowMusicSheetCalculator} from "./MusicalScore/Graphical/VexFlow/VexFlowMusicSheetCalculator";
 import {MusicSheetReader} from "./MusicalScore/ScoreIO/MusicSheetReader";

src/MusicalScore/Graphical/VexFlow/VexFlowMusicSheetDrawer.ts

@@ -2,7 +2,6 @@ import Vex = require("vexflow");
 import {MusicSheetDrawer} from "../MusicSheetDrawer";
 import {RectangleF2D} from "../../../Common/DataObjects/RectangleF2D";
 import {VexFlowMeasure} from "./VexFlowMeasure";
-import {GraphicalMusicSheet} from "../GraphicalMusicSheet";
 import {ITextMeasurer} from "../../Interfaces/ITextMeasurer";
 import {PointF2D} from "../../../Common/DataObjects/PointF2D";
 import {GraphicalLabel} from "../GraphicalLabel";