adding tests for non matched sequence
sequence mapping implemented and tested, included stringify-key to use it to match key combinations
map module handles key combinations
some refactoring of match making (separated out insert mode)
refactored out insert-mode
no longer exposing normal/insert mode functions on vim
adding documentation to map module and making API more consistent (only work with string or array of chars)
using parseKey to parse keys in test harness and starting to test immediate maps in insert mode
map immediate in insert mode working unit tested and manually checked