wesnoth_addon_manager: Add missing trailing newline to _info.cfg
addon/info: wesnoth_addon_manager wants the dependencies list in _info.cfg
wam: Write title and type fields to _info.cfg like the C++ client does
wam: Make our _info.cfg's look identical to the C++ client's

To achieve this, add the same leading comment section ("do no edit this
file", etc.) and use the same indentation format as the C++ engine, and
don't use quotes around the uploads attribute value (it's an integer).
Update changelog for recent wam changes