Older manifests break build process

[codeanticode]

Recent versions of the Android SDK require the android:exported attribute in the manifest file, in the main application or service sections. Also, the uses-sdk section is no longer needed, as min-sdk and target-sdk versions are set in the gradle build file.

Even though a solution to fix this problem is simply to delete the manifest file from the sketch folder so the mode will create a new, valid one, this might be confusing, so better if the mode can detect those older manifests and fix them by itself.

[codeanticode]

Fixed with 4277e21