[u104][vim] 1. Avoiding escape timeout. 2. new key mappings. 3. plugin configurations.

1. Avoiding escape timeout issues in vim

   (new key mappings)
2. <f9> Use tagbar by default and taglist as backup
3. <c-f*> may not works for mintty; Add mappings of all <c-f*> key to <leader><f*>
4. <f3> To save current session; load it by 'vip' command.

   (plugin configurations)
5. Enable auto-close/focus for tagbar/taglist/gundo.
6. Some configurations modification for ycm/syntastic