[Tizen][Runtime] Add support for installer signals.

Currently when install/uninstall/update Crosswalk app, xwalk-pkg-helper
will manipulate Tizen pkgmgr DB directly with
pkgmgr_parser_parse_manifest_* APIs. We need to call
pkgmgr_installer_send_signal in the helper to broadcast package status
change events, therefore they can be used by Application API.

BUG=XWALK-1446
Merge pull request #1872 from shaochangbin/send-signal

[Tizen][Runtime] Add support for installer signals.