[JCLOUDS-474] refactor SoftLayer support
JCLOUDS-40: Unasync Rackspace Cloud Identity
JCLOUDS-622: Remove most vestiges of InputSupplier

Guava 16 deprecated InputSupplier and a future release will remove it.
JCLOUDS-549: Fix NPE in LoginCredentials.toString

- also deprecates LoginCredentails.get(Password|PrivateKey)
- use getOptionalPassword and getOptionalPrivateKey instead
JCLOUDS-622: add Strings2.toString(InputSupplier)

We did not deprecate this in 1.7.x as previously thought.
Address Checkstyle violations
Close streams in integration tests

Also remove bogus delete workaround.  Previously unclosed
FileInputStream caused test failures on Windows which cannot delete
open files.  Found with Kohsuke's file-leak-detector.
Enable more filesystem integration tests

Other tests will require Java 7 xattr support.
Replace const.txt file input with synthetic inputs

This commit replaces file resource-based test inputs with in-memory
equivalents.  This is more consistent and efficient than the previous
approach.  Also resized some test inputs to be partSize + 1 instead of
2 * partSize.  Tested against aws-s3, blobstore, core, cloudfiles-us,
and filesystem.
JCLOUDS-554: Update Nova default API to v2
Add support for filesystem last modified
Use xattr for filesystem blob metadata

Proof of concept, do not commit.  This relates to some discussion in
JCLOUDS-626.  Relies on JDK 7 features which jclouds 2.0 will require.