Upgrade to logback 1.1.2

Changelog:
http://logback.qos.ch/news.html
JCLOUDS-410: Remove InputStreamSupplierPayload

ByteSourcePayload replaces this.  jclouds 1.7 deprecated
InputStreamSupplierPayload and Guava 16 deprecated InputSupplier
itself.
JCLOUDS-417: Remove ConsumeOnCloseInputStream

ConsumeOnCloseInputStream can potentially perform a copy in finalize()
if the stream was not closed properly.
JCLOUDS-417: Test closing a stream w/o reading it
Enforce correct MD5 for local blobstores

Matches behavior of real blobstores.
Remove unneeded InputSupplier helper

Also convert byte[] to HashCode.
JCLOUDS-622: Deprecate Strings2.toString

Guava 16 deprecated InputSupplier.
Improve use of ByteSource with test resources

This commit ensures proper resource cleanup, simplifies
initialization, and paves the way for purely synthetic inputs in a
subsequent commit.
JCLOUDS-40: Unasync OpenStack Nova API