Change README.md: minor grammar fixes and word refactoring.
Change vimrc: Add augroup formatting and add :set spell autocmd

I added the augroup 'formatting' and put all autocmds that have to do
with vim formattin in there. There are two autocmds that set options and
two that unset them.
Change vimrc: now uses setlocal
Change vimrc: add gitcommit to file list for autocmds in formatting