Fixed segmentation fault when bad torrent metainfo is parsed.
Added dynamic_cast properly to detect the misconfiguration of
metainfo
and then throw exception or skip it.
* src/DefaultBtContext.{h, cc}
* test/DefaultBtContextTest.cc
* src/AnnounceList.cc
* src/CompactPeerListProcessor.cc
* src/message.h
* src/DefaultBtAnnounce.{h, cc}
* test/DefaultBtAnnounceTest.cc
* src/BencodeVisitor.cc
Added the ability to recognize url-list in a torrent file.
The retrieved URLs are attached to the corresponding FileEntry.
* src/DefaultBtContext.{h, cc}
* src/FileEntry.{h, cc}
* test/DefaultBtContextTest.cc
