Move String.toAction -> Action.split
Extract Action.nav
Clean up Core.String.goLeft/Right
Experiment with types for Core.Array and Core.String
WIP: Splitting Entries on enter key
Implement Array.split
WIP: Implementing split for Entries
Entry.split works for children of the root node
Entry.split uses Array.do instead of Array.split for more flexibility in handling nodes
Enter splits the current Entry