[R-pkgs] diffobj released to CRAN

[brodie gaslam]

diffobj provides tools to compare the visual representation of R objects using the Myer's diff algorithm:

## Example:
> mx1 <- matrix(1:9, 3)
> mx2 <- mx1[-2,]
> diffPrint(mx1, mx2, format="raw")
< mx1                  > mx2
@@ 1,4 @@              @@ 1,3 @@
.       [,1] [,2] [,3]         [,1] [,2] [,3]
. [1,]    1    4    7    [1,]    1    4    7
< [2,]    2    5    8  ~
. [3,]    3    6    9    [2,]    3    6    9

This is similar to `tools::Rdiff`, but is easier to use directly with R objects, has colorized output if your terminal supports it, has semantic-aware handling of the text output of R objects, and does not require the GNU diff utility to be available on the system.

See the vignette for more details <https://cran.r-project.org/web/packages/diffobj/vignettes/diffobj.html>, and the Github page to submit issues <https://github.com/brodieG/diffobj>.

Many thanks to Uwe Ligges and Kurt Hornik for their patience with my first CRAN submission.

Brodie Gaslam.