Improve implementations, code style, and tests

[turbolent]

• Use the latest version of the Flow CLI, the Cadence 1.0 preview release is outdated
• Make the code more consistent, by fixing whitespace, improving argument labels, removing unnecessary type annotations, etc.
• Replace implementations with functions (e.g. String.contains) and functionality (e.g. InclusiveRange) built into Cadence now. In some cases this makes the code much more efficient, e.g. InclusiveRange does not allocate a whole array of indices like before
• Extend the test cases

[turbolent]

@bjartek @austinkline Would be great to get this merged, so we can update the Cadence Source Compatibility Suite, which currently uses a fork with these changes: https://github.com/onflow/cadence/blob/master/compat/suite/green-goo-dao-flow-utils.yaml

[austinkline]

LGTM, @bjartek any objections?

[bjartek]

No