cli: update to Go modules and remove dep support
readme: add Buy Me A Coffee link
ci: test with Go 1.10
Don't use coverage and race detector at the same time which adds
allocations that can cause some tests to fail.
all: update copyright notice
Add Help command and help articles
Also improve the documentation somewhat and add more examples.
Actually use the closure in the example
Fix error in docs
Try to make documentation clearer (again)
Expand documentation and example
Use CommandSet in example
Add initial Command implementation