Use vital-over.
Update document.
Add <Tab>
Fix keymapping.
Fix keymapping.
Update vital.vim
Merge branch 'vital' into ver.2.0

Conflicts:
	autoload/over/command_line.vim
Restore substitute.
Add load function.
Fix prompt.
Fix typo.
Fix substitute preview.
Add autocmd User.
Update document.
Fix default keymapping.
Update document.