Using custom keymaps

[thomasheyenbrock]

Support for different keymaps has been added in #2501. However we only import the sublime keymap by default. If one would simply pass a different keyMap prop (e.g. vim) CodeMirror will throw an error.

I see two possible solutions (cc @acao):

• Either we keep the behavior and properly document that users have to import custom keymaps themselves.
• Or we import the chosen keymap(s) on runtime dynamically.