splitRange and ProtectedRange

[oleibman]

Fix #1457, which had gone stale but is now re-opened. The Coordinate::splitRange method expects a string of cell ranges, but it is a bit limited. Excel sometimes uses comma for union and space for intersection, and sometimes vice versa. splitRange uses comma for union, and doesn't do anything with spaces. This PR adds a new method Coordinate::allRanges which handles both union and intersection, and adds a parameter to indicate whether comma means union or intersection (with space meaning the other). Also, since the issue specifically mentioned this as a problem for ProtectedRange, an allRanges method is added to that class.

This is:

• a bugfix
• a new feature
• refactoring
• additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change and a link to the pull request if applicable
• Documentation is updated as necessary