The tutorial should perhaps contain an FFI section, but this one is too long.

It's already covered in the types section.

fix issue #3222

Doesn't work cross-crate yet.

Now you can write:

extern {
  f() -> int;
}

and f will be accessible in the enclosing scope.

tutorial: adding link and reference to sublime text package.

Use struct+impl syntax instead of the (deprecated) struct with embedded methods syntax. Also standardise the comment indentation and add some whitespace between items.

1. from_bytes, from_bools and from_fn were not exported but should have been.
2. lots of stuff that either didnt exist or didnt need exporting was being exported.

use native log2 function and enable freebsd tests in uv_ll