properly slash paths passed to UnityBegin in test runner generator

auto/generate_test_runner.rb

@@ -290,7 +290,7 @@ class UnityTestRunnerGenerator
     output.puts("int main(void)")
     output.puts("{")
     output.puts("  suite_setup();") unless @options[:suite_setup].nil?
-    output.puts("  UnityBegin(\"#{filename}\");")
+    output.puts("  UnityBegin(\"#{filename.gsub(/\\/,'\\\\')}\");")
     if (@options[:use_param_tests])
       tests.each do |test|
         if ((test[:args].nil?) or (test[:args].empty?))