[Vim] Add plugin vim-cscope.

Change-Id: Ia525f5612edad1804b09fdcab4cf468f0b31b6f8
Signed-off-by: Wei-Chung Wen <morisato3711@gmail.com>
[Bash] Add firefox to PATH.

Change-Id: Icd0f7499e6eeefeafa497f0145d254f01d5e379a
Signed-off-by: Wei-Chung Wen <morisato3711@gmail.com>