1. Cleaned up help pages to simplify categories, updated terms and conditions;
2. Modified R package to allow reading of NEE in new units, Rnet to be composed of SWnet+LWnet;
3. Shortened some R error messages, but by no means comprehensive.
Merge pull request #75 from edenduthie/gab

1. Cleaned up help pages to simplify categories, updated terms and condi...