Converter: add "ignore case" modifier for regular expressions for replacing units, types and functions.

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42492 4005530d-fff6-0310-9dd1-cebe43e6787f
Converter: tweak messages

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42493 4005530d-fff6-0310-9dd1-cebe43e6787f