Removed min and target version from manifest

We don't need to set min and target version here as it is already defined in the build.gradle.
+ it should fix 

`Execution failed for task ':MyApp:processDebugManifest'.
> Manifest merging failed. See console for more info.
Main manifest has <uses-sdk android:minSdkVersion='10'> but library uses minSdkVersion='14'`