Enhancements to various ACL-related CLI tools

+ Moved staging and tftp server definitions to global settings
  to allow for site specific configuratons
+ Improvedd output in bin/netdev when a search returns no results
+ Added bin/check_syntax tool to help visibility into ACL parsing
+ Added tftpy package to trigger.packages.tftpy (MIT License)
+ Added force10 support to bin/load_acl
A little more debug logging and error-handling to bin/load_acl
Bugfix causing reactor hang when ssh & telnet fail (fix #129)

- Use defer.fail to return the exception instead of raising it
Documentation for migrating from acl. prefix to any filename
Improved user output and help text in bin/acl (fix #147)

- -l and -m args now print a message when load queue is empty
- Clarified help text for -a and -r args
Improve --help text for bin/acl with usage and description
Bugfix in bin/load_acl causing infinite loop w/ >1 device

- All closures within activate() changed to use positional args;
  no longer using default args within function scope.
Updated docs for CSV support to match reality