Merge branch 'release/0.6.16'
Merge branch 'release/0.6.17'
Merge branch 'release/0.6.18'
Make g:pymode_rope_map_space key configurable
Fix lint check error when buftype is nofile
Add g:pymode_lint_ignore_files to ignore files which explicitly disagree
with pep8 (YouCompleteMe, for example)