flip 2.4.3.0021

• Added name to flip.object-class
• Updated @useDynLib flip, .registration = TRUE in flip-object.R
• Added missing class listOrNULL
• Updated .RBuildignore and .gitignore
• Removed period from the Title
• Added missing dependencies stats, graphics, utils
• Added mention to LICENSE file in the DESCRIPTION
• Created end exported generic for show()
• Exported all the methods
• Added explicit call to arma::
• Removed wrang definition to rom() in permSpace.R
• Added request for import plyr in DESCRIPTION
• Added limit to Rcpp
• Added support for testthat
• Added a NEWS.md file to track changes to the package.