documentation fixes, and remove debug dependency on file_pool structure layout

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@9979 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
update copyright year

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@9981 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda