Static mode of jira issues macro (default) cannot handle capitalised column names

Steps to reproduce:

• add jira issues macro to a page
• modify the list of columns to be 'Key;Summary'
• notice how the Summary column is not shown when the page is saved.

Dynamic mode could handle column names in a case insensitive way whereas static mode cannot. This is a critical issue because we have changed the default mode of the macro from dynamic to static. Meaning once people upgrade they might have problems if they defined custom column list with capitalised names.