Yaml arrays

Add support for simple lists of values to the parameter system. These are formatted like:

key: [v1,v2,v3]
key: ["abc","def","ghi"]

We also allow the [] to be optional. They don't add much, just extra syntax.

Strings can be quoted or unquoted and have quotes or commas inside. We do not support multi-line lists or lists in lists. That would require a lot more work.

Other changes are changing the output order so that values are written into their section once (we don't allow repeated sections) and the refactoring of the various get param functions to all use single generic macro implementations.

A misfeature in parser_set_param is fixed, that didn't add a new section if needed.

We also add new functions for trimming white space from (mutable) strings.