Changes between versions of the dataframe package.
Most recent changes are first.

---- 2.5	5/20/2012
Merge in changes to R data frame code as of R 2.15.0 (use paste0()).
Add help files and edit NAMESPACE so R CMD check works.

---- 2.4	3/28/2012
Fix as.data.frame.list for case that list has no names.
(Discovered by Stephen Kaluzny.)

---- 2.3	3/13/2012
Merge in changes to R data frame code as of R 2.14.2.

Add a description of the differences in the code.

---- 2.2	10/2/2009
Add new version of Math.data.frame - skips non-numerical variables
instead of failing.  This is useful for e.g. print(round(x)).

---- 2.1	10/1/2009
Add new version of as.data.frame.list

---- 2.0	9/28/2009
Modify core routines to avoid making copies of data, and avoid checking
for duplicate row names if possible.

x[[k]] <- value gives an error if x has fewer than k-1 columns, rather
than producing an illegal data frame.

Add doc/memory.R and doc/speed.R showing memory and speed differences.

---- 1.1	9/16/2009
Add tests/*.t and tests/runTests.R

---- 1.0	9/13/2009
Original version, copy data frame code from R
