<at-select> issues (with repro)

[chuyik]

Hey, I found two issues of <at-select>:

1. Cannot select options with arrow keys if data is load asynchronously, which will throw Uncaught RangeError: Maximum call stack size exceeded.

   Steps to reproduce: a. click the input to focus b. press down arrow

2. Options list won't show up if I modify the value of the selected option.

   Steps to reproduce: a. select an option b. click the input twice to unhighlight the value c. modify the value by pressing backspace key

Reproduce link: Codepen