A Wrapper Function for Instant Package Installation / Loading

Since library() and require() only accept input with length(input) = 1 it is necessary to make repeated calls - this can be quite annoying.. So, HERE is a little wrapper function for convenient package installation / loading. It installs packages if they are missing and loads them if there were not loaded yet. I have put it to my RProfile.site so I can conveniently install / load packages with only one call and am quite content with it..