Switched from cloudfiles to pkgcloud for Rackspace storage.
Updated tests involving Rackspace storage and sample config.
Bumped version to 0.1.13.
Added missing protocol for sample authUrl.
Added configurable preset separator to allow something other than an underscore in your remote file names (ie, a slash).
Added a simple cache for Rackspace client and container definitions.
This speeds up multiple file uploads considerably.  The S3 methods could also take advantage of this, but will not be as significantly improved.
Added Local storage option and created test for it
Allow for giving array of storage options to Imager constructor
Modified test to verify multiple storage options
Added Local storage example
Fixed some incorrect references to this.storage
Added keepNames option to variants to preserve original filenames.
Improved temp file name generation.
Moved temp file unlinking closer to generation.
removed call to os.tmpDir
Fix for recursive directory creation on Linux (starting with /)

Missing Local storage option for test.
Eliminated a race condition in upload() method (with async.map).
add tests for express form uploads
add examples for express form uploads