Create cmd-enter mapping to 'o' in insert mode.

vimrc

@@ -179,8 +179,10 @@ nnoremap Vat vatV
 " Insert mode mappings {{{1
 " emacs style jump to end of line
 imap <C-e> <C-o>A
+imap <C-a> <C-o>I
 " Open line above (ctrl-shift-o much easier than ctrl-o shift-O)
-imap <C-S-o> <C-o>O
+imap <C-Enter> <C-o>o
+imap <C-S-Enter> <C-o>O
 " Easily modify vimrc {{{1
 nmap <leader>v :e $MYVIMRC<CR>
 " http://stackoverflow.com/questions/2400264/is-it-possible-to-apply-vim-configurations-without-restarting/2400289#2400289