Remove implied read phone state permission

If minSdkVersion and targetSdkVersion are not defined, they default to 1, and according to
the docs
(http://developer.android.com/reference/android/Manifest.permission.html#READ_PHONE_STATE)
> if _both_ your minSdkVersion and targetSdkVersion values are set to
> 3 or lower, the system implicitly grants your app this
> [READ_PHONE_STATE] permission

So, every app including the library as packaged & uploaded in Maven
will automatically ask for this permission, even if not defined in the
app's AndroidManifest.xml, since the manifest merger will add it.

The relevant message of the manifest merger is in file
build/outputs/apk/manifest-merger-${appname}-report.txt
> android:uses-permission#android.permission.READ_PHONE_STATE
> IMPLIED from AndroidManifest.xml:2:1 reason: kankan.wheel.widget has a targetSdkVersion < 4