+ Fixed setNumericRounding(0), more tests added.
+ Added integer64 support in grouping and joins (tests there but switched off until fully works)

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/datatable@1243 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
integer64 grouping and join tests turned on and pass

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/datatable@1244 edb9625f-4e0d-4859-8d74-9fd3b1da38cb