Fixed objectSummaries

Fixed bug with objectSummaries. Now, more than 1000 summaries can be
returned.   To avoid memory issues, this version returns a stream.  Of
course, that stream can be converted to a list. Addresses #29 ans #32 
Thanks. I just tried but unfortunately your test failed.

```
INFO: Unable to execute HTTP request: Timeout waiting for connection
org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection
	at org.apache.http.impl.conn.PoolingClientConnectionManager.leaseConnection(PoolingClientConnectionManager.java:232)
	at org.apache.http.impl.conn.PoolingClientConnectionManager$1.getConnection(PoolingClientConnectionManager.java:199)
	at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at com.amazonaws.http.conn.ClientConnectionRequestFactory$Handler.invoke(ClientConnectionRequestFactory.java:70)
	at com.amazonaws.http.conn.$Proxy9.getConnection(Unknown Source)
	at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:456)
	at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
	at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
	at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:402)
	at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:245)
	at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:3573)
	at com.amazonaws.services.s3.AmazonS3Client.deleteObject(AmazonS3Client.java:1755)
	at com.amazonaws.services.s3.AmazonS3Client.deleteObject(AmazonS3Client.java:1740)
	at awscala.s3.S3$class.deleteObject(S3.scala:207)
	at awscala.s3.S3Client.deleteObject(S3.scala:234)
	at awscala.s3.Bucket.delete(Bucket.scala:53)
	at awscala.S3Spec$$anonfun$1$$anonfun$apply$mcV$sp$2$$anonfun$apply$1.apply(S3Spec.scala:37)
	at awscala.S3Spec$$anonfun$1$$anonfun$apply$mcV$sp$2$$anonfun$apply$1.apply(S3Spec.scala:37)
	at scala.Option.map(Option.scala:145)
	at awscala.S3Spec$$anonfun$1$$anonfun$apply$mcV$sp$2.apply(S3Spec.scala:37)
	at awscala.S3Spec$$anonfun$1$$anonfun$apply$mcV$sp$2.apply(S3Spec.scala:37)
	at scala.collection.immutable.List.foreach(List.scala:318)
	at awscala.S3Spec$$anonfun$1.apply$mcV$sp(S3Spec.scala:36)
	at awscala.S3Spec$$anonfun$1.apply(S3Spec.scala:15)
	at awscala.S3Spec$$anonfun$1.apply(S3Spec.scala:15)
	at org.scalatest.Transformer$$anonfun$apply$1.apply$mcV$sp(Transformer.scala:22)
	at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)
	at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
	at org.scalatest.Transformer.apply(Transformer.scala:22)
	at org.scalatest.Transformer.apply(Transformer.scala:20)
	at org.scalatest.FlatSpecLike$$anon$1.apply(FlatSpecLike.scala:1639)
	at org.scalatest.Suite$class.withFixture(Suite.scala:1121)
	at org.scalatest.FlatSpec.withFixture(FlatSpec.scala:1683)
	at org.scalatest.FlatSpecLike$class.invokeWithFixture$1(FlatSpecLike.scala:1636)
	at org.scalatest.FlatSpecLike$$anonfun$runTest$1.apply(FlatSpecLike.scala:1648)
	at org.scalatest.FlatSpecLike$$anonfun$runTest$1.apply(FlatSpecLike.scala:1648)
	at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)
	at org.scalatest.FlatSpecLike$class.runTest(FlatSpecLike.scala:1648)
	at org.scalatest.FlatSpec.runTest(FlatSpec.scala:1683)
	at org.scalatest.FlatSpecLike$$anonfun$runTests$1.apply(FlatSpecLike.scala:1706)
	at org.scalatest.FlatSpecLike$$anonfun$runTests$1.apply(FlatSpecLike.scala:1706)
	at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:413)
	at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:401)
	at scala.collection.immutable.List.foreach(List.scala:318)
	at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
	at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:390)
	at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:427)
	at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:401)
	at scala.collection.immutable.List.foreach(List.scala:318)
	at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:401)
	at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:396)
	at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:483)
	at org.scalatest.FlatSpecLike$class.runTests(FlatSpecLike.scala:1706)
	at org.scalatest.FlatSpec.runTests(FlatSpec.scala:1683)
	at org.scalatest.Suite$class.run(Suite.scala:1423)
	at org.scalatest.FlatSpec.org$scalatest$FlatSpecLike$$super$run(FlatSpec.scala:1683)
	at org.scalatest.FlatSpecLike$$anonfun$run$1.apply(FlatSpecLike.scala:1752)
	at org.scalatest.FlatSpecLike$$anonfun$run$1.apply(FlatSpecLike.scala:1752)
	at org.scalatest.SuperEngine.runImpl(Engine.scala:545)
	at org.scalatest.FlatSpecLike$class.run(FlatSpecLike.scala:1752)
	at org.scalatest.FlatSpec.run(FlatSpec.scala:1683)
	at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:444)
	at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:651)
	at sbt.TestRunner.runTest$1(TestFramework.scala:84)
	at sbt.TestRunner.run(TestFramework.scala:94)
	at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:219)
	at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:219)
	at sbt.TestFramework$.sbt$TestFramework$$withContextLoader(TestFramework.scala:207)
	at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:219)
	at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:219)
	at sbt.TestFunction.apply(TestFramework.scala:224)
	at sbt.Tests$$anonfun$7.apply(Tests.scala:196)
	at sbt.Tests$$anonfun$7.apply(Tests.scala:196)
	at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:45)
	at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:45)
	at sbt.std.Transform$$anon$4.work(System.scala:64)
	at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:237)
	at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:237)
	at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:18)
	at sbt.Execute.work(Execute.scala:244)
	at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:237)
	at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:237)
	at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:160)
	at sbt.CompletionService$$anon$2.call(CompletionService.scala:30)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
```