add var_pop for float8, var_samp for float4
bugfix: StromError_ReCheckByCPU still remained
add skelton of opencl_numeric.h
add pg_strom.opencl_devices
update startup log
add pgstrom_restrack_cleanup_context()
Merge branch 'master' into blkload
add special case handling on pgstrom_release_data_store for transaction break
bugfix: infinite loop to parse pg_strom.opencl_devices
Merge branch 'master' into blkload