v0.2: Improved error handling and output

Changes:

• Use exceptions to handle errors and pass them to the script, rather than calling sys.exit from the module.
• Use warnings.warn to handle warnings and catch these in the script.
• Implement colourised print messages along with the --nocolour flag to disable them.
• Move click.command to the script rather than the module.

v0.1: Initial release

While this is an initial release, the code should be considered reliable and production ready.

Error handling should be mostly complete and give useful messages. If you have any issues or encounter errors that could be handled better, please create an issue on GitHub.