Changed the 'clam' output columns.
Merge branch 'master' of https://github.com/SimonGoring/neotoma
A number of changes based on comments from package collaborators.

* Fixed typo in `get_contact` and added `length`  as `fun.aggregate` for the contacts so that a warning isn't thrown.  It doesn't do anything anyway.
* `get_dataset` was changed to provide a `Site` component that lines up with the one in `get_site`.
* `get_site` now allows a dataset to be passed so that a set of datasets can be converted easily into sites.  We should do the same for downloads if it's not already like that.
* `get_download` now accepts datasets and pulls out the DatasetID so that we don't have to do that annoying `lapply`/`sapply` thing anymore.
Rebuilt the package, updates to `Rd` files followed.  All based on the last commits.
Merge pull request #101 from SimonGoring/master

Changes associated with SimonGoring/neotoma_paper comments
Merge pull request #6 from ropensci/master

Um.  I might be doing something wrong.
Fixing `README.md` to resolve issue #97.

* Changing the plotting for both the mammoth and publication example.
* Changes to `get_publication` to improve `data.frame` behavior by setting `stringsAsFactors=FALSE`.
*  New plots for mammoth and publications.
Merge pull request #102 from SimonGoring/master

Improvements to README and `get_publication`.
Merge pull request #100 from gavinsimpson/master

document contributors in the CRAN-approved manner
Merge pull request #7 from ropensci/master

Changing the DESCRIPTION file.
Create `download` class and add behaviour similar to lists.
Based on discussion in https://github.com/SimonGoring/neotoma_paper/issues/5 I have created a `download` and `download.list` class.  `download`s are single dataset downloads.  `download.list`s are sets of downloads.  `download`s now also include a timestamp using `Sys.time`.
Merge pull request #104 from SimonGoring/master

Adding the `download` and `download.list` classes.
Added classes, cleaned up data formats, built new tests.
* Added classes for `download`, `dataset` and `site` objects.
* Added 'time accessed' for datasets and downloads.
*  Created `print` methods for `site`s and `download`s.
* moved parameter checking to `param_check` for all methods to reduce clutter.
Merge remote-tracking branch 'upstream/master'
Merge pull request #105 from SimonGoring/master

Adding classes for download and dataset objects
I forgot to add the roxygen stuff for `param_check`.
Merge pull request #106 from SimonGoring/master

I forgot to add the roxygen stuff for `param_check`.
Merge pull request #8 from ropensci/master

Um, weird. . .
Merge pull request #107 from SimonGoring/master

Merge pull request #8 from ropensci/master
Fixed S3 method declarations.
The methods weren't working because I didn't declare the `x` in the first function call.  I think its fixed now, but RStudio doesn't give us tab completion anymore.