Failure [INSTALL_FAILED_VERSION_DOWNGRADE I don’t see anything fatal in your logs.
What this error potentially indicates is the fact that you have installed the same app on device but with higher code version.
What I can suggest is to first try to uninstall any plugin app demos you have on the test device. Even if it’s from Google Play.
With any smartphone it’s easy just uninstall the app.
For emulator start new emulator or try to uninstall the app using one of these: http://stackoverflow.com/questions/12949609/adb-shell-command-to-make-android-package-uninstall-dialog-appear
Hope it will help.