fix pause, piece picker, and bandwidth limit bugs

libtorrent/include/libtorrent/bandwidth_manager.hpp

@@ -398,6 +398,7 @@ private:
 					block_size = m_limit
 						/ (m_limit / max_bandwidth_block_size);
 				}
+				if (block_size > qe.max_block_size) block_size = qe.max_block_size;
 			}
 
 			if (amount < block_size / 2)

libtorrent/src/piece_picker.cpp

@@ -639,7 +639,7 @@ namespace libtorrent
 		if (dp == m_downloads.begin()) return;
 		int complete = dp->writing + dp->finished;
 		for (std::vector<downloading_piece>::iterator i = dp, j(dp-1);
-			i != m_downloads.begin() && j != m_downloads.begin(); --i, --j)
+			i != m_downloads.begin(); --i, --j)
 		{
 			assert(j >= m_downloads.begin());
 			if (j->finished + j->writing >= complete) return;

libtorrent/src/session_impl.cpp

@@ -1068,7 +1068,16 @@ namespace detail
 						&& !t->is_seed()))
 				{
 					if (!i->second->is_choked() && t)
+					{
+						policy::peer* pi = p->peer_info_struct();
+						if (pi && pi->optimistically_unchoked)
+						{
+							pi->optimistically_unchoked = false;
+							// force a new optimistic unchoke
+							m_optimistic_unchoke_time_scaler = 0;
+						}
 						t->choke_peer(*i->second);
+					}
 					continue;
 				}
 				peers.push_back(i->second.get());