Fixed writeTextToCanvas to properly position the text with padding above and below the glyph.  Previously it was doubling the padding so it was always rendering the glyph at the very top of the canvas
Fixed writeTextToCanvas to properly position the text with padding above
and below the glyph.  Previously it was doubling the padding so it was
always rendering the glyph at the very top of the canvas

AnalyticalGraphicsInc/cesium,CesiumGS/cesium,jasonbeverage/cesium,YonatanKra/cesium,YonatanKra/cesium,YonatanKra/cesium,CesiumGS/cesium,jasonbeverage/cesium,CesiumGS/cesium,YonatanKra/cesium,CesiumGS/cesium,likangning93/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium,progsung/cesium,likangning93/cesium,likangning93/cesium,likangning93/cesium,progsung/cesium,likangning93/cesium