Added gradle support

Change-Id: Ia5a04830b15ca0d57e746cd20723ee9a214ccbe6
Added eclipse project files

Change-Id: I96d2dff9864e0de538711176b12c61ffa8061b1a
deprecated old static factories and public constructors in favor of static factories that return joda or long timestamp

Change-Id: I88908e2ef377dd16ce3a28677b7ded353856b2ff