use message() instead of print()

[jonathancallahan]

First off, thanks for this package!! It's short and sweet and does exactly what we need. We have a couple of packages that help provide and organize spatial metadata associated with environmental monitoring:

• https://github.com/MazamaScience/MazamaSpatialUtils
• https://github.com/MazamaScience/MazamaLocationUtils

Our packages need to be able to work well for both analysts sitting in front of RStudio and also inside of batch scripts. For batch scripts we typically ignore messages intended for a human user. This is easy to do if underlying code consistently uses message(), warning() and stop(). However, for any packages that print() or cat() we have to write specialized code using capture.output() in order to run things in verbose = FALSE mode.

I think it would be a general improvement if you swapped out all use of print() for message().

[mhudecheck]

Glad you like it! We're prepping an update to CRAN over the next couple of days. I'll go ahead and swap out print() for message().