Conversion to click

This includes a mess of changes:
 * stricter option parsing (ex: global options are specified directly after sl)
 * no prefix-based option matching that doc-opt did
 * entrypoint-based loading
 * Several CLI cleanups:
 ** The options in create-options
 ** Remove help command
 ** Renames dns subcommands to include zone- and record-
 ** Removes dns edit subcommand (because it was a mess). Just remove and add records.

This is not a finished thought. Every module under the SoftLayer.CLI.modules
module still needs to be converted. Unit tests need to be adjusted. Documentation
needs to be updated.
Conversion to click

This includes a mess of changes:
 * stricter option parsing (ex: global options are specified directly after sl)
 * no prefix-based option matching that doc-opt did
 * entrypoint-based loading
 * Several CLI cleanups:
 ** The options in create-options
 ** Remove help command
 ** Renames dns subcommands to include zone- and record-
 ** Removes dns edit subcommand (because it was a mess). Just remove and add records.

This is not a finished thought. Every module under the SoftLayer.CLI.modules
module still needs to be converted. Unit tests need to be adjusted. Documentation
needs to be updated.
pep8 cleanup
Adds image module to new system