By emitting Lua code to call translate() and pcdata(), we are more
flexible than when doing this internally in the parser. The performance
penalty should be negligible.

We need a bit less escaping this way.

Also fix all warnings.

Open with O_CLOEXEC, use fstat() instead of stat().

The gluon-web package is basically a stripped-down and refactored version
of the LuCI base.