Merge pull request #2 from USGS-R/master

Vignette Section 2 Pull
changed wording of section 2 to data structure rather than data frame because arrays are included
Merge branch 'master' of github.com:schristel-USGS/USGSHydroOpt
Continued to work on section 2 of the vignette. Specifically, I added two sections on arrays --one describing arrays for USGSHydroOpt && one showing how such arrays can be produced with USGSHydroOpt
Finished section 2 started section 3 which goes through fxns for creating summary optical variabls.
Merge pull request #6 from schristel-USGS/master

Updating section 2 and 3 of vignette