Column Widths, Especially for ODS

[oleibman]

Fix #3609. Reporter created a spreadsheet with non-adjacent columns having non-default widths. Ods Writer needs to generate entries for the missing columns with default width.

The fix was fairly simple. Testing it was not. Ods Reader basically ignores all styles; they are complicated, declared in (at least) 2 places (content.xml and styles.xml). This change deals only with the problem as reported, in which the missing declarations should be in content.xml. If someone reports a real-world example of this involving styles.xml, I can look at that then. In the meantime, this toehold might serve as a template for adding other style processing to Ods Reader.

Looking at other formats, processing of column widths was also missing from Html Reader, and is now added. Note that this will work only with inline Css declarations on the col tags, which can be generated by Html Writer using setUseInlineCss(true). This creates a much larger file than one created without inline CSS.

A general problem became evident when studying the code. Worksheet columnDimensions is an unsorted array. This is not a problem per se, but it can easily lead to unexpected results from a getColumnDimensions call. The code is changed to sort the array before returning it in getColumnDimensions.

One existing test failed as a result of this change. It erroneously tested getHighestColumn instead of getHighestDataColumn, which caused a problem because the final column declaration included a number-columns-repeated attribute. The new result for getHighestColumn is correct, and the test is changed to use getHighestDataColumn instead, which was certainly its intent.

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

Why this change is needed?

Provide an explanation of why this change is needed, with links to any Issues (if appropriate).
If this is a bugfix or a new feature, and there are no existing Issues, then please also create an issue that will make it easier to track progress with this PR.