JetBrains/ideavim — pull request #23 by mavenraven (2014-02-22 05:20:22+00:00)
Title: adds support for VIM-518, VIM-448

Adds support for "jj" style escape chords. Allows defined
chords to be read in from a user's .vimrc, where the chord is
defined like:
inoremap jk

Allows allows the setting of a custom escape in ex mode with:
:inoremap jk