Merge branch 'dev'

- add test
- fix history emulation with `stay`
- improve pseud-visual highlight
- minor performance improvement: do not always generate direction
  specific patterns
Bump up version to 0.9.2

- minor update
- fix change log style
Redraw for non-<expr> mappings
Use non-expr mapping for normal & visual mode

- TODO: handle stay command
Add comments for TODO of expr-mappings
Fix stay command for non-expr mappings
Fix histadd for non-expr stay command
Fix offset handling for stay command
spec: fix test cases

- skip offset suite because feedkeys() cannot be tested
doc: add note for <expr> mappings restriction for autocmd
spec: add highlight test
Merge branch 'non-expr' into dev