new: g:startify_empty_buffer_key

This variable can be used to create a second mapping for creating the
empty buffer.

Closes #10.

doc/startify.txt

@@ -68,6 +68,15 @@ configuration.
 Put these variables into your vimrc. The shown assignments are also the
 default values.
 
+============-
+
+    let g:startify_empty_buffer_key = ''
+
+This creates an additional, hidden mapping for the empty buffer.
+
+Example: let g:startify_empty_buffer_key = 'o'
+
+
 ============-
 
     let g:startify_session_dir = '~/.vim/session'
@@ -100,11 +109,13 @@ The amount of files to list.
 
 ============-
 
-    let g:startify_bookmarks = [ '~/.vimrc' ]
+    let g:startify_bookmarks = []
 
 A list of files to bookmark. Those files will always be shown at the bottom of
 the start screen.
 
+Example: let g:startify_bookmarks = [ '~/.vimrc' ]
+
 ============-
 
     let g:startify_skiplist = []

plugin/startify.vim

@@ -92,6 +92,10 @@ function! s:insane_in_the_membrane() abort
   nnoremap <buffer><silent> e :enew<cr>
   nnoremap <buffer><silent> <cr> :normal <c-r><c-w><cr>
 
+  if exists('g:startify_empty_buffer_key')
+    execute 'nnoremap <buffer><silent> '. g:startify_empty_buffer_key .' :enew<cr>'
+  endif
+
   autocmd! startify *
   autocmd startify CursorMoved <buffer> call s:set_cursor()
   autocmd startify BufWipeout <buffer> autocmd! startify *