fix links
java.lang.ClassCastException for SpiceService$SpiceServiceBinder

To fix java.lang.ClassCastException: android.os.BinderProxy cannot be cast to com.octo.android.robospice.SpiceService$SpiceServiceBinder.
Null detection for spiceService is missing.

Null detection for spiceService is missing onServiceDisconnected. Since spiceService might be null onServiceConnected. And also checked all null detections in rest of SpiceManager class.
Make cachedRequest equal method better, removal unsymmetrical behaviour. Rehabilitation of InvalidServiceTest
Merge branch 'shenwill-patch-1'