Skilletcli

Bugfix

* Fixes issue with pyinstaller binary on *nix

Package Naming Change

This is a rename of the "panos" package within skilletcli to a more apt name "panosxml". This resolves a conflict with the newly renamed pandevice package.

**bugfixes**
* Re-implemented the ability to specify arbitrary git repos (i.e not in the github index).

**New features**
* added a dockerfile for those whom prefer docker than running a local python3 environmnt.

This is the official release of the skilletCLI client side utility. Package components (such as Remotes or Panos) will continue to have features added to them as is required by client-side code, however, the CLI utility is effectively feature-complete at this stage.

__New Features__
* Github based skillet indexing! Using --repository without additional arguments will provide a list of Github hosted skillets to choose from. Repopath is no longer required, but can still be optionally provided if the skillet is not centrally indexed.
* Much improved branch handling. --branch without arguments now lists available branches and there is more logical defaults.
* API repo type is now production! --repotype api can be used as an alternative to Git when Git is not supported.

__New Features__
* Support for parsing non-IS style repos (snippets in root directory).
* Remotes: Included Github as a valid index type for Skillet repositories.
* Test suite expanded and improved.

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