Last breaking change into mod system (will explain on forum)
- paths in "filesystem" node are now relative to mod directory
- "filesystem" entry in mod.json is now optional
- made "register object" log messages visible only in log
- minor fixes, including #1173

git-svn-id: https://vcmi.svn.sourceforge.net/svnroot/vcmi/trunk@3099 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834