Support multiple registered frames in CanJS Panel

[phillipskevin]

• show a dropdown next to "CanJS Components" header to allow user to select which frame to debug (similar to dropdown in chrome console)
• add frame option to helpers.runDevtoolsFunction

[phillipskevin]

Here is an unstyled example:

The code was added to the prototype: https://github.com/canjs/can-devtools-components/commit/f03a796d6ea050e59853d9fa348c47d52c40aa6b

[phillipskevin]

Here is how it looks in chrome's devtools:

[ryangwilson]

https://codepen.io/ryangwilson/pen/zyvzeX