check RStudio project

[ThierryO]

• check for existing RStudio project file
• use 2 spaces for tab
• UTF-8 encoding
• 1 Rproj at the repo root
• 1 Rproj at the package root (in case package root != repo root)
• no Rproj files in subfolders of the package
  • inst and its subfolders can hold max 1 Rproj per (sub)folder
• git config --local is set so that \r\n is replaced with \n
• check package building settings

[ElsLommelen]

To which extend could enforcing these Linux standards (UTF-8 and \n) possibly cause problems when packages are used in Windows 7? Up to now I haven't come across such problems, but in this case it would be nice to have the possibility of a motivated exception. (Only needed as long as Windows 7 is used at INBO, so you might choose to leave it as is and change it temporary if these rules cause problems.)

[ThierryO]

The \n is a git thing and should not affect Windows users. On Windows, git will store Windows style line ending as Unix style line endings in the git history.

I've not seen any issue with the UTF-8 setting so far. I'd enforce this until further notice. We can reconsider if it causes unfixable problems.