单独build launcher.

　　$cd

　　$export TOP='pwd'

　　$source build/envsetup.sh

　　$cd packages/apps/Launcher

　　$mm

　　将build出来的launcher.apk push到SDK当中

　　$adb push out/..../system/app/Launcher.apk /system/app

　　$adb shell stop zygote

　　$adb shell start zygote