Replaced "" with static const variable A2STR::NIL.
Replaced string comparison against "" with std::string::empty().
Added PROTO_* to Request class and use them as a protocol string
constant.
Made "started", "stopped", "completed" static const variable in
AnnounceList class.
Reads URIs from stdin when "-i -" is specified.
* src/UriFileListParser.h, src/UriFileListParser.cc: Removed.
* src/UriListParser.h, src/UriListParser.cc: New class.
* src/StreamUriListParser.h: New class.
* src/FileUriListParser.h: New class.
* src/main.cc (main): Use StreamUriListParser and
FileUriListParser
instead of UriFileListParser.