Use vm functions for deleting sounds and costumes

Update Dropdown Menus On Click

Update dependencies

Closes #345

Closes #344

Closes #352

Closes #346

https://greenkeeper.io/

https://greenkeeper.io/

Listen for the monitor update from the VM

Fix squashed blocks in flyout when adding a sprite while on another tab

Only listen to targets updates

Thanks @paulkaplan

This reduces the complexity of the reducer, as well as how frequently it's run. The VM will emit a targets update after a step if any target info has changed.

Add Save and Load buttons

/ht @paulkaplan

Integrate VM serialization changes