Addd support for XML and textid-like properties for extract-i18n

JIRA ticket: https://jira.appcelerator.org/browse/TC-2732

I know this regexp will also match `setTi.Locale.getString` and because of the `i` switch also `l()`, but he existing regexp *also* matches cases `setTi.Locale.getString` and since it's an non-intrusive feature, I say it's acceptable.