Fix R CMD check warning & note

[your-highness]

normR builds and checks succesfully but some issues remain.

The following warning is shown:

* checking whether package 'normr' can be installed ... WARNING
Found the following significant warnings:
  Warning: replacing previous import 'IRanges::windows' by 'grDevices::windows' when loading 'normr'
See 'C:/Users/biocbuild/bbs-3.13-bioc/meat/normr.Rcheck/00install.out' for details.

The following note is shown:

* checking installed package size ... NOTE
  installed size is  5.4Mb
  sub-directories of 1Mb or more:
    extdata   2.2Mb
    libs      2.4Mb