Merge pull request #26 from lyokha/master

fixes in folding
Overhaul keyboard module

Allow for WYSIWYG toggles for emphasis and strong. Only those are
enabled by default.
Merge branch 'master' of github.com:vim-pandoc/vim-pantondoc
Fixed YAML headers ending in ... not being folded correctly
Implement verbatim, strikeout, superscript and subscript operators