[refactor] extract often used classes from lib\NetPacks.h to separate header - less dependecies on whole packets class tree

[mingw build] fix linking issues with netpacks. 
Mingw build is finally fixed! 

[c::b] update projects

[config] fix and cleanup spell_info.json


git-svn-id: http://svn.code.sf.net/p/vcmi/code/trunk/@3711 4dfc6b2a-8b31-0410-aa91-d6c70e3ac834