Prevent printing blank line when members are less than methodCount. (#78)

* Prevent printing blank line

Prevent printing blank line when Trace members are less than methodCount.

Author: filipedfs

lib/src/printers/pretty_printer.dart

@@ -132,7 +132,8 @@ class PrettyPrinter extends LogPrinter {
     for (var line in lines) {
       if (_discardDeviceStacktraceLine(line) ||
           _discardWebStacktraceLine(line) ||
-          _discardBrowserStacktraceLine(line)) {
+          _discardBrowserStacktraceLine(line) ||
+          line.isEmpty) {
         continue;
       }
       formatted.add('#$count   ${line.replaceFirst(RegExp(r'#\d+\s+'), '')}');