We would like to allow developers to use async/await
on the inside (Node.js) of Lumi programs.
We now support (don't error on) usage of async/await
inside runtime callbacks in Lumi programs. If await is
used during deployment, it will trigger an error.
Also adds support for try/catch in LumiJS, as these are
used more heavily in async/await code.
Since we target Node.js environments without native support
for async/await, we also emit runtime helpers to support TS
transpilation of async/await for Node.js pre-7.6.