merge error code fix from RC_1_0

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10139 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
hide make_error_code function from documentation

git-svn-id: http://libtorrent.googlecode.com/svn/trunk@10140 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda