* Drop bradfitz/iter dependency
`range iter.N` looks nice and doesn't allocate, but unfortunately using a `range` expression blocks a function from being inlined wherever it's used (for now). It's not that we need inlining in all cases, but I do think a C-style for loop looks just as nice and is probably clearer to the majority. There also aren't any clear disadvantages to changing (unless you just happen to dislike the look of C)
* Update misc_test.go
* Update rlreader_test.go
* Update torrent_test.go
* Update bench_test.go
* Update client_test.go
* Update iplist_test.go
* Update mse_test.go
* Update peerconn_test.go
* Update peerconn.go
* Update order_test.go
* Update decoder_test.go
* Update main.go
* Update bench-piece-mark-complete.go
* Update main.go
* Update torrent.go
* Update iplist_test.go
* Update main.go
torrent-create and torrent-verify did not work correctly when a single
file is present in metainfo torrent file. torrent-create now fails if
the path passed as an argument does not exist. I've als modified
dht.go which now handles the case when an empty string is passed in
DHT bootstrap nodes slice. Finally in span.go I've sneaked in cheekily
a change which defines a type more like idiomatic Go (I have an OCD :-))
Piece state is broken up into several dimensions.
Implement keep-alive in connection writer.
Lazily hash pieces, only as requested.
Replace client actor mechanism with a mutex.
Fix runConnection/connectionLoop/handshake misnomers.
Fix broken reading from partially complete pieces.
YenForYang
Matt Joiner
BonkaBonka
Milos Gajdos