[datatable-help] Two very minor glitches with v1.8.4 on R <= 2.15.0

[Matthew Dowle]

On R 2.15.1 and 2.15.2, there are no known problems.

The glitches are :

i)  Test 764 fails in 2.15.0 and earlier: X[Y] where Y is an empty (0 
row) data.table.
     An error message about pmin() is issued, rather than an empty 
data.table.
     In R 2.15.1 there was this (relied on by test 764) :
       "pmin() and pmax() now also work when one of the inputs is of 
length zero and
        others are not, returning a zero-length vector".

ii) If setnames is passed character 'old' but detects duplicate column 
names exist,
     the error will be "paste0 not found", rather than the intended 
error message.
     paste0() was added to 2.15.0.

All other tests (including after 764) pass fine in R >= 2.12.0, as 
intended and stated.

These could and should have been caught (by me) before release to CRAN, 
apologies.

Not planning to release a patch to CRAN, unless anything else comes up.

Matthew