Enhanced CTorrent Code

Fix an issue which could cause request reassignment instead of duplication in endgame mode.

Some unchoke rework, including new seeding algorithm

Some peer and peerlist efficiency improvements

Need to initialize m_stagedir memory

Track disk access in a global flag for greater flexibility.

Base idle determination on nominal rates when not using bw limits.

Clean/shrink cache after flushing data on download completion.

-C option doesn't work.
"Flushing all cache" indicates writing/flushing pieces that aren't.
Clean/shrink cache after flushing data on download completion.

Reduce global flags

Improve relative time format