Added --event-poll option to select the method for polling
events.
The available methods are "select" and "epoll". "epoll" is
available on Linux only. The earlier release has the compile
option to choose from these methods.
* configure.ac
* src/RequestGroupMan.cc
* src/OptionHandlerFactory.cc
* src/EpollEventPoll.h
* src/StreamFileAllocationEntry.cc
* src/a2io.h
* src/SelectEventPoll.h
* src/option_processing.cc
* src/prefs.h
* src/EpollEventPoll.cc
* src/EventPoll.h
* src/SocketCore.h
* src/Makefile.am
* src/main.cc
* src/DownloadEngine.h
* src/SelectEventPoll.cc
* src/DownloadEngine.cc
* src/SocketCore.cc
* src/DownloadEngineFactory.cc
* src/Makefile.in
* src/prefs.cc
* src/usage_text.h