~/.vimrc: don't show mode in focus mode.

.vimrc

@@ -33,6 +33,14 @@ if isdirectory($HOME . '/.vim/bundle/vundle')
	Bundle 'kchmck/vim-coffee-script'
	Bundle 'junegunn/goyo.vim'
	function! g:goyo_before()
		set noshowmode
	endfunction
	function! g:goyo_after()
		set showmode
	endfunction
	let g:goyo_callbacks = [function('g:goyo_before'), function('g:goyo_after')]
endif
" Have syntax highlighting and non-vi features