Include line number with syntax errors

I have been converting a lot of templates from another templating language to mustache. These templates have a deep partial tree and so often I will need to write many files before I can run them to see if they work after converting them by hand. Since I'm human, I make mistakes almost constantly and found it helpful to have mustache.php tell me what line the syntax error occurred on. The file name is included in the stack trace but if anyone has any thoughts on how to make this error reporting even better I would love to incorporate them into my pull request. =)