Merge pull request #153 from SimonGoring/master

Cleaning up the print methods and closing out some issues.
use inherits for determing and acting upon class information
use inherits for determing and acting upon class information
use inherits for determing and acting upon class information
 * use inherits for determing and acting upon class information
 * streamline an sapply call to not use an annonymous function
use inherits for determing and acting upon class information
correct typo iherits -> inherits
Built `bind` method for sites, downloads and datasets to join multiple search results.
- not implemented: search and warn for duplicates
- Made sure all datasets had names assigned in the dataset_list
- rebuilt package.
Merge pull request #154 from gavinsimpson/use-inherits

Use inherits() to ascertain class information
Merged @gavinsimpson's weird indents and didn't want to fix it back.

Merge remote-tracking branch 'upstream/master'

Conflicts:
	R/get_dataset.R