Patch by adrian_broher removing boost filesystem v2 support

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7800 dbd5520b-6a0a-0410-a553-f54834df5b05
Patch by vincele removing unused stuff

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7801 dbd5520b-6a0a-0410-a553-f54834df5b05