Clarifies error messages and updates README acknowledgment for POWER …

…data (#84)

README.Rmd

@@ -21,8 +21,7 @@ It is only an API client that allows easy access to the data.
 {nasapower} does not redistribute the data or provide it in any way, *we encourage users to follow the requests of the POWER Project Team and properly acknowledge them for the data rather than citing this package* (unless you have actually used it in your work).
 
   >*When POWER data products are used in a publication, we request the following acknowledgement be included:
-   "These data were obtained from the NASA Langley Research Center POWER Project funded through the NASA Earth
-   Science Directorate Applied Science Program."*
+   "The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) Prediction of Worldwide Energy Resource (POWER) Project funded through the NASA Earth Science/Applied Science Program."*
 
 The previous statement that properly cites the POWER data is different than the citation for {nasapower}.
 To cite this R package, {nasapower}, please use the output from `citation(package = "nasapower")` and cite both the package manual, which includes the version you used and the paper which refers to the peer-review of the software package as the functionality of the package has changed and will likely change to match the API in the future as necessary.

README.md

@@ -25,9 +25,10 @@ properly acknowledge them for the data rather than citing this package*
 (unless you have actually used it in your work).
 
 > *When POWER data products are used in a publication, we request the
-> following acknowledgement be included: “These data were obtained from
-> the NASA Langley Research Center POWER Project funded through the NASA
-> Earth Science Directorate Applied Science Program.”*
+> following acknowledgement be included: “The data was obtained from the
+> National Aeronautics and Space Administration (NASA) Langley Research
+> Center (LaRC) Prediction of Worldwide Energy Resource (POWER) Project
+> funded through the NASA Earth Science/Applied Science Program.”*
 
 The previous statement that properly cites the POWER data is different
 than the citation for {nasapower}. To cite this R package, {nasapower},