- vcmi can now calculate crc32 checksum of a file
- reorganized internal filesystem structure - all files from one mod are
now grouped in same FS node
- modhandler will now calculate crc32 checksum for each mod
- modhandler now knows validation status of each mod

todo - use checksum to determine mods that have not changed since last
start and disable validation for them.


git-svn-id: http://svn.code.sf.net/p/vcmi/code/trunk/@3607 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834