Merge pull request #20 from sirkonst/fix_nlst

Fixed ftp command NLST without arguments.
Fixes some issues brought up from landscape.io
Merge branch 'master' of github.com:softlayer/swftp
Adds tests for long directory listings
Fixes bug in swift client involving markers.

Whenever marker was used, it would mistakenly send an end_marker
parameter as well with the value "None". This caused listings >
10,000 not to function properly in most cases.

Added tests for FTP/SFTP and the swift client itself testing
listings greater than 10,000 objects.

Should fix #21.
Adds rewrite_storage_scheme and rewrite_storage_netloc options

 * This adds the ability to slightly rewrite the storage URL returned from swift's auth.
   This allows implementers to force the use of HTTP instead of HTTPS or to use a
   specific hostname and/or port
Adds filtering to log observers

At the moment, it only lets through log events with a system that starts with 'SwFTP' and '-'
* swftp.logging.StdOutObserver - outputs logging to stdout
* swftp.logging.LOG_USER, swftp.logging.LOG_LOCAL0, etc. - Outputs to log facility
Adjusts README.md bullet points
Update README.md