[spec/interpreter] Make sources build and run with current Sphinx & P…

…ython

[interpreter] Makefile tweaks

[interpreter] Release 2.0 package

[spec] "version 2.0" -> "release 2.0" (#1452)

Add a test for non-treelike behavior of stack (#961)

We've recently found a bug in a WebAssembly library we've been working
with where we're mapping WebAssembly to a tree-like IR internally. The
way we parse into this representation, however, has a bug when the
function isn't itself tree-like but rather exibits properties that
exploit a stack machine. For example this isn't so straightforward to
represent in a tree-like fashion:

    (import "" "a" (func $foo))
    (import "" "b" (func $foo (result i32)))
    (func (result i32)
      call $b
      call $b
      call $a
      i32.xor)

The extra `call $a` in the middle is valid `WebAssembly` but needs
special treatment when converting to a more tree-like IR format. I
figured it'd be good to ensure there's a spec test covering this case as
we currently pass the suite of spec tests but still contain this bug!

[interpreter] Don't suppress deprecation warnings

[interpreter] Make deprecation warning non-fatal

[interpreter] Unify assert_result* assertions (#1104)

Add commands to generate Working Draft

* `make WD-tar`: Generate the Working Draft tar file to submit
* `make WD-echidna`: Publish the Working Draft via Echidna

Marking gh-pages used for fPWD