Start application and get runnables list by homescreen-service

As title, I made some changes in homescreen-service, libhomescreen, launcher, homescreen, mainly purpose as below:

1. In homescreen or launcher when starting application it only need call showWindow.

2. When launcher starting, it get runnalbes list from homescreen-service, and after
   install/uninstall application launcher can get "app_list_change" event to update application list.

3. Specially, I want to use "ws" interface instead "dbus" interface.

About changes:

• homescreen-service(please reference hs-class.png)
  # start application in showWindow. Please reference start_application.png
  # add "getRunnables" verb. Please reference runnables.png
  # handle "application-list-changed" event from afm-main and add "application-list-changed" event. Please reference app_list_change.png

• libhomescreen
  # add getRunnables interface.
  # add Event_AppListChanged event.

• homescreen
  # only call showWindow when start application

• launcher
  # only call showWindow when start application
  # get runnalbes list from homescreen-service
  # subscribe and deal with Event_AppListChanged

sourcecode
homescreen-service
libhomescreen
homescreen
launcher