Remove "allowBackup" from this file

allowBackup=true collides with apps that try to include AboutLibraries and use allowBackup=false on their own manifest. Gradle Build V > 0.10.0 will fail. The solution suggested by gradle (add tools:replace="allowBackup" to application element) does not work.
Merge pull request #19 from kashban/patch-1

Remove "allowBackup" from this file