[common] Move files commonly used to /server/commn.

Recently the number of source files has been increased. So this patch organizes
them by moving source files for libhatohol-common.so, which is used from both
Hatohol server and Hatohol Arm Plugins.
[client][test] Add a common directory to launch Hatohol server.
[server/QUICK-REF] Update an example.
[test][launch-hatohol-for-test] Fix a type in the path: server_idr -> server_dir.
[server] Arrange some source files.

HatoholArmPluginBase and HapZabbixAPI are used only from Hatohol
Arm Plungins, not Hatohol server. So they should be in 'hap' directory.
Merge pull request #510 from project-hatohol/make-common-dir-2

Make common dir 2