add server/client functions

add server/client functions

test_app2ext usage has been changed.
now, all the test can be tried to.

install example)
pre-condition: prepare /tmp/org.example.basicuiapplication-1.0.0-arm.tpk
1. (tizenglobalapp)$test_app2ext --pre-install
2. (tizenglobalapp)$pkgcmd -it tpk -p {pkg_path}
3. (tizenglobalapp)$test_app2ext --post-install
4. (tizenglobalapp)$test_app2ext --enable (mount external part)
5. (tizenglobalapp)$test_app2ext --disable (unmount external part)

Change-Id: I8d4d3c07f4632228d7cb15c015012c095a365c4d
Signed-off-by: jongmyeongko <jongmyeong.ko@samsung.com>