Rename files with .r extension to .R

[jamesmbaazam]

This PR addresses the spring cleaning checklist in #156 by renaming all R scripts with .r extension to .R to standardize the extensions. The differences in extensions was a remnant of legacy scripts.

Achieving this on git was quite tricky so I'll document it here for future sake.

The issue was that git was not recognising the renamed files even though I changed my configuration to git config core.ignorecase false. I used R's rename.files() first but that did not work.

Here's what worked:

• I used the terminal to rename the files to an arbitrary .x extension using mv ./R/filename.r ./R/filename.x.
• I git added and committed them.
  - I did them individually for some reason (maybe because of the trauma of having to start over again many times)
• I then renamed the .x extensions to .R using the same mv ... command.
• I then git added and git committed them. Voila!