Configure my own tags path and cscope.out path

Signed-off-by: apporc <appleorchard2000@gmail.com>
Use noremap, add --fields=+l for ctags so that YCM can use it.

Signed-off-by: apporc <appleorchard2000@gmail.com>
Disable (Close vim if the only windows open is nerdtree)

Signed-off-by: apporc <appleorchard2000@gmail.com>
Let YCM collect identifiers from tags file

Signed-off-by: apporc <appleorchard2000@gmail.com>