Determin _threadtholdSpeed in each constructor for
ActivePeerConnectionCommand and PeerReceiveHandshakeCommand.
* src/ActivePeerConnectionCommand.{h, cc}
* src/PeerReceiveHandshakeCommand.{h, cc}
* src/BtSetup.cc
* src/BtConstants.h
Use PREF_MAX_DOWNLOAD_LIMIT as a threshold for
ActivePeerConnectionCommand when it is given and
PREF_MAX_DOWNLOAD_LIMIT < default threshold.
* src/ActivePeerConnectionCommand.{h, cc}
* src/BtSetup.cc
Implemented BitTorrent/http/ftp integrated download.
I've rewritten lots of files and now some headers have forward
class declarations to reduce compile time.
The implementation is extremely alpha stage, I recommend to use this
for testing purpose only.