added ignore list
Started updating package to httr

- Started addressing issue #11
- ebirdgeo now uses httr.
- Also changed ip retriever to a faster one. http://ipinfo.io/developers
- Started first stab at unit tests. See issue #14

Now this just needs to be propagated to the remaining functions and then we can remove RCurl. Also, many missing inputs can be quickly caught using assertions.
Merge pull request #16 from ropensci/httr_fix

httr fix
update from upstream/master
Merge branch 'master' into latlng_func