rebird v0.2 released to CRAN

rebird 0.2

NEW FEATURES

• Added two new functions ebirdfreq and ebirdregioncheck, which provide historical frequency of observation data and check whether a region is valid under eBird, respectively.

MINOR IMPROVEMENTS

• Passed along curl options to httr functions
• Replaced RJSONIO with jsonlite
• Replaced plyr with dplyr