chore: re-license under MPL-2.0
doc: update examples
- the previous examples were synchronous,
making the progress bars display only after they complete,
thus not highlighting the strength of separating NewBar and Start
doc: add and improve specificity of doc comments
doc: add examples to README
fix: thread-safe NewBar and completion checks
doc: fix broken method links
test: leap across progress bars
feat: add Bars.Done to print newline on finish
test: add example tests
- they all need to be reviewed manually every time as they fail due to
escape sequences
doc: add godocs.io link to README