Add support for PolicyTemplate items

Add support for PolicyTemplate items #46

Fix: Error in version comparaison

Fix: Error in version comparaison #44

Check for values in the configuration elements

Check for values in the configuration elements: if so, exit with failure status.

Add a new flag to enable this check:

 -e, --empty-config   Check for values in the configuration
                        elements: if so, exit with failure status.

Provide an option to export diff files to a specific folder

Provide an option to export diff files to a specific folder when a conflict is detected

Add a new option to specify a diff destination folder:

-d, --diff PATH   A folder where to generate unified diff
                     files output

Support for non UTF8 and non colorized output(s)

Add two new flag to enable specific output formating:

-a, --ascii     Only use ASCII symbols to display results
-b, --no_color  Do not colorized the output

MacOSX and Windows support

Note for Windows users:

Windows usage is supported with some limitations:

• No colored output.
  • Currently I have no idea on how to fix this.
• Some UTF-8 symbols used in output are only with some fonts like DejaVu Sans Mono.
  • In future, I will try to implement a version of script that do not request UTF-8 support to return results.

vro-package-diff is now a Pypi hosted project

Changes

• vro-package-diff is now a Pypi hosted project: vro-package-diff and so, can be installed with pip install command.
• An endpoit vro-diff to access to the tool from any path location.
• Usage of click to manage:
  • inputs packages
  • help
  • legend display
  • test feature
• A test feature
• Documentation is hosted on vro-package-diff.readthedocs.io
• Travis pipeline