Update Cell.java

换行的行高计算多了2px，导致换行较多时段落出现大段空白

ureport2-core/src/main/java/com/bstek/ureport/model/Cell.java

@@ -596,7 +596,7 @@ public class Cell implements ReportCell {
 			lineHeight=cellStyle.getLineHeight();
 		}
 		fontSize=fontSize*lineHeight;
-		int singleLineHeight=UnitUtils.pointToPixel(fontSize);//fontMetrics.getHeight();
+		int singleLineHeight=UnitUtils.pointToPixel(fontSize)-2;//fontMetrics.getHeight();
 		if(textWidth<=totalColumnWidth){
 			return;
 		}