factor out error handling in lazy_bdecode

git-svn-id: http://libtorrent.googlecode.com/svn@9935 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
move string_tokenize out of i2p_stream and add unit test for it

git-svn-id: http://libtorrent.googlecode.com/svn@9936 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
fix build

git-svn-id: http://libtorrent.googlecode.com/svn@9937 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda