Issue #77 : Fix one number format related bug. Thanks antipro

src/xlsx/xlsxstyles.cpp

@@ -168,11 +168,12 @@ void Styles::fixNumFmt(const Format &format)
             bool find=false;
             while (it.hasNext()) {
                 it.next();
-                if (it.value() == id)
+                if (it.value() == id) {
                     const_cast<Format *>(&format)->fixNumberFormat(id, it.key());
                     find = true;
                     break;
                 }
+            }
 
             if (!find) {
                 //Wrong numFmt