follow vim-vspec conventions, add some testcases
rename some <Plug> mappings

    clever-f -> clever-f-f
    clever-F -> clever-f-F
    clever-t -> clever-f-t
    clever-T -> clever-f-T
fix mapping names
fix column at multibyte test
remove useless test command, add some usages
add g:clever_f_across_no_line to move in single line
add note
Special Thanks
follow the rename of <Plug> mappings
check maparg of <Plug> mappings