treat EINTR returns as a BREAK (now mapped to SWITCH_STATUS_INTR), we appriciate the interrupted syscalls but we would like to continue working properly

         otherwise the channel name is not set in 'show channels'

merge code from xml-rpc trunk - fix xml-rpc not terminating on windows on fs unload - only effect windows build

         Added hunting scheme to support new ftdm_call_place API
         Make ftdm_channel_call_answer use ftdm_channel_call_indicate with FTDM_CHANNEL_INDICATE_ANSWER
         Updated doxygen docs in freetdm.h