Rolled back a change to handling duplicated names for joins because tests are not added yet. Removed spaces in test.

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1271 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Replaced 'chmatch2' with a ~14x faster version. Perhaps this function could be useful and should be exported?

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1272 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
When DT is empty, DT[, newcol:=max(b), by=a] now properly adds the column. Closes #5376.

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1273 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Closes #5714. DT[, j, with=FALSE] when length(j)=0 returns null data.table properly as before now. Fixed a possible regression.

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1274 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Closes #5435. print.data.table repeats 'digits=' argument for list columns as well.

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1275 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Added NCOL to tables()

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1276 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Merge branch 'refs/heads/r-forge-svn-local'