vimrc: add F12 :SyntasticReset

vimrc

@@ -63,6 +63,7 @@ let g:syntastic_check_on_wq = 0
 let g:syntastic_mode_map = {'mode': 'passive', 'active_filetypes': [], 'passive_filetypes': []}
 let g:syntastic_enable_signs = 0
 nmap <F11> :SyntasticCheck<cr>
+nmap <F12> :SyntasticReset<cr>
 
 let g:ctrlp_match_func = {'match': 'pymatcher#PyMatch'}