[Bash] Add custom Vim into PATH.

Change-Id: I6639f3a4a0426a76ed7eea5556a226102cdde16c
Signed-off-by: Wei-Chung Wen <morisato3711@gmail.com>
[Vim] Enable relativenumber by default.

Change-Id: Id39d1ede15516703492271590c35bf8a55a70950
Signed-off-by: Wei-Chung Wen <morisato3711@gmail.com>