Boolean logic short circuiting should lazily resolve variable references

[d0c-s4vage]

Describe the bug

Short circuiting in 010 editor does not resolve variables until the actual comparison is made. E.g., consider the 010 template below:

local int a = 1;
if (a || DOES_NOT_EXIST) {
    Printf("Short circuit power!\n");
}

In 010 Editor, the string Short circuit power! is printed.

In pfp, the error UnresolvedID: Could not resolve field 'DOES_NOT_EXIST' is raised.

Stack Trace

Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/james/__ws__/dev/pfp/pfp/__main__.py", line 61, in <module>
    main(sys.argv)
  File "/home/james/__ws__/dev/pfp/pfp/__main__.py", line 55, in main
    keep_successful=args.keep,
  File "/home/james/__ws__/dev/pfp/pfp/__init__.py", line 91, in parse
    printf=printf,
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 846, in parse
    res = self._run(keep_successful)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1051, in _run
    traceback,
  File "/home/james/__ws__/dev/pfp/venv3/lib/python3.6/site-packages/six.py", line 695, in reraise
    raise value.with_traceback(tb)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1024, in _run
    res = self._handle_node(self._ast, None, None, self._stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1133, in _handle_node
    res = self._node_switch[node.__class__](node, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1177, in _handle_file_ast
    self._handle_node(child, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1133, in _handle_node
    res = self._node_switch[node.__class__](node, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 2374, in _handle_if
    cond = self._handle_node(node.cond, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1133, in _handle_node
    res = self._node_switch[node.__class__](node, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1878, in _handle_binary_op
    right_val = self._handle_node(node.right, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 1133, in _handle_node
    res = self._node_switch[node.__class__](node, scope, ctxt, stream)
  File "/home/james/__ws__/dev/pfp/pfp/interp.py", line 2044, in _handle_id
    raise errors.UnresolvedID(node.coord, node.name)
pfp.errors.PfpError: UnresolvedID: Could not resolve field 'DOES_NOT_EXIST' at /tmp/tmpm_y_oum_:2
Exception at test.bt:2

To Reproduce

Run the provided 010 template

Expected Behavior

pfp should lazily resolve referenced variables during boolean logic operations

Implementation/Fix Notes/Thoughts

This could either be really easy, or really hard.