Fix 'on_sources' typo
Fix wrong keymap definition
Add 'zv' to keymaps to automatically open folds

'zv' - Recursively open the foldings at the cursor line
'zz' - Make the cursor line at the center of the window
Add condition check for vim-arpeggio
Remove 'vim-submode'

`g+` and `g-` can be repeated with 'vim-repeat' (`.`) thus vim-submode
is no longer required.
Tidy up
Integrate autocmd group
Tidy up