* [R] MSVC compatibility
* [GPU] allow seed in BernoulliRng up to size_t and scale to uint32_t
* R package build with cmake and CUDA
* R package CUDA build fixes and cleanups
* always export the R package native initialization routine on windows
* update the install instructions doc
* fix lint
* use static_cast directly to set BernoulliRng seed
* [R] demo for GPU accelerated algorithm
* tidy up the R package cmake stuff
* R pack cmake: installs main dependency packages if needed
* [R] version bump in DESCRIPTION
* update NEWS
* added short missing/sparse values explanations to FAQ
* [R] make sure things work for a single split model; fixes#2191
* [R] add option use_int_id to xgb.model.dt.tree
* [R] add example of exporting tree plot to a file
* [R] set save_period = NULL as default in xgboost() to be the same as in xgb.train; fixes#2182
* [R] it's a good practice after CRAN releases to bump up package version in dev
* [R] allow xgb.DMatrix construction from integer dense matrices
* [R] xgb.DMatrix: silent parameter; improve documentation
* [R] xgb.model.dt.tree code style changes
* [R] update NEWS with parameter changes
* [R] code safety & style; handle non-strict matrix and inherited classes of input and model; fixes#2242
* [R] change to x.y.z.p R-package versioning scheme and set version to 0.6.4.3
* [R] add an R package versioning section to the contributors guide
* [R] R-package/README.md: clean up the redundant old installation instructions, link the contributors guide
* [R-package] JSON tree dump interface
* [R-package] precision bugfix in xgb.attributes
* [R-package] bugfix for cb.early.stop called from xgb.cv
* [R-package] a bit more clarity on labels checking in xgb.cv
* [R-package] test JSON dump for gblinear as well
* whitespace lint
