stationaRy 0.5.1

Update the internal history_tbl object
Eliminate testthat tests that get data from the NOAA server to consistently pass CRAN checks

stationaRy 0.5.0

Complete rewrite of package.
Package now has the main function get_met_data(), where get_station_metadata() and station_coverage() provide information on the station and which additional data fields they have reported on.
The get_met_data() function can bucketize observations so that even hourly observations are provided.
Instead of needing to provide a range of years, any vector of years can be provided to get_met_data().
The visibility parameter is now provided in the standard set of station observations.
A more reliable method of getting the local times for each station has been implemented.
Meteorological data files can be collected in a directory after download for later reuse.
Additional data fields, when requested, are processed much more quickly than in previous releases.
Tibbles are now returned instead of data frames.
A pkgdown site has been generated.

Removes the get_tz_offset() function, the large shapefile object, and the dependencies on the lubridate, sp, and proj4 packages.
Greater use of dplyr functions to greatly increase processing speed.
Functions are resilient to missing years of data within year ranges provided.

Added function get_ncdc_station_info() to obtain data frame of all known met stations, and, to filter list of stations by geographic bounding box and/or by years of available data.
Added function select_ncdc_station() to take the data frame produced by get_ncdc_station_info() and aid in obtaining a selection of a single station; the resulting identifier string can be passed to get_ncdc_station_data() to fetch data for the selected station.

Contains function get_ncdc_station_data() (to fetch data and create a data frame) and helper function get_tz_offset() (to determine time zone offset and correct times to local time).