Updated regex to fix to issue #21

RegEx now works with files that are escaped with a ```\n``` character. Added optional quotes around the a and b file to support lines in the raw diff that look like this. 

```diff --git "a/system/cms/config/database.php\n" "b/system/cms/config/database.php\n"```

This type of file appears when a file is saved with a ```\n``` at the end of it.