+ fastorder.c forwards now adapts to counting/qsort based on n and range.
+ cummulator and memset in counting adapt to n<range
+ working memory globalized
+ localized issorted turned off to simulate almost sorted input (need to turn on again for production)
+ included iradix from Arun, tweaked and tested, but not yet hooked up

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/datatable@1079 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
+ Turned on localised is.sorted test in fastorder forwards.
+ Added bench() of fastorder to setkey.  May turn into calibrate() one day to tune forwards adaptive parameters to user's hardware.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/datatable@1080 edb9625f-4e0d-4859-8d74-9fd3b1da38cb