[Lazarus] New XML format for project info files

[Juha Manninen]

I finally changed the XML format for Lazarus projects.
It means the list of units and buildmodes etc.
The format was not ideal because adding or removing an item resulted a
big diff and potential merge problems.
See this report for details:
 https://bugs.freepascal.org/view.php?id=22752
The patch is by Ondrej.
Please test with Lazarus trunk r60683.

Regards,
Juha