Revealed by R CMD check + running all tests
Also ensure development mode set up succesfully - should always be true on CRAN
Use package-wide options to set some preferences. Fixes #94.
Those are things that users might what to change often: - the path where devel packages are installed: `~/R-dev` is a little intrusive - the github user name: developer might want to use theirs
Contributed mostly by Andrew Redd. Closes #91
Contributed by Andrew Redd. Fixes #92