remove data/okstations.R; add data/okstations.rda

data/okstations.rda is a dataframe with metadata of oklahoma
mesonet stations.
data/okstaitons.R was a script to download an updated list.
remove .onAttach function from okmesonet.R; do not update okstation
on package startup
use checkgeoinfo in okmesonet.R
remove 'data' from checkgeoinfo() and downloadstn() docs
remove assigning variable in updatestn()
update documentation for November 2014
patch to fix downloading of Oklahoma Mesonet station list

The original configuration downloaded the Oklahoma Mesonet station list
when the package was first installed and when loaded. This was deemed
excessive by CRAN administrators. The station list is now included as
an installed list, with the ability of the user to manually download
and update as desired using updatestn().

Merge branch 'okstations' into develop