Added translation support for php files with javascript heredoc

[NickvdMeij]

This code checks for 'lajax.t' function within PHP javascript heredocs. This allows for javascript translations within a php file.

[lajax]

Thanks for the PR but this solution is too specific

[NickvdMeij]

@lajax Then what would you like to see different? Because the company I work for would love to see such a feature (translating in heredocs and/or strings) implemented in the translate manager. If you point my in the right direction, I can make another pull request with a less "specific" implementation