Add following spll version info:
--wrsSpllVersion
--wrsSpllBuildDate

Additionally:
--update Makefile
--update MIB
--update init.c
--increase version number of spll_stat structure due to new fields
--support version 2 of spll_stat structure in wrsSpllStatusGroup

Please note that this commit requires changes done in wrpc-sw commit:
revision: report build information via spll_stats structure
Signed-off-by: Adam Wujek <adam.wujek@cern.ch>