[xwalkdriver] Init Web Driver failed on Tizen ivi

Add app_launcher command to launch tizen app, we won't use xwalkctl
or xwalk-launcher any more

BUG=https://crosswalk-project.org/jira/browse/XWALK-2951
Merge pull request #5 from wuyuehang/tizen-ivi_20141117.2

[xwalkdriver] Init Web Driver failed on Tizen ivi