Merge pull request #147 from SimonGoring/master

Fixing conflicts from branch merge with ropensci/neotoma doc_fix
Changes to clean up problems resulting for standardization.  Making sure all the examples run and are informative.
- `compile_downloads.R` removed sapply and lapply commands in the example, added plotting.
- `compile_taxa` moved the warnings into the `down.to.df` function, made sure the `download_list` class was retained.
- `get_download` removed the `metadata` in the example.
- rebuilt the package.
ran `run_examples` in `devtools` and found some problems with the examples.  All examples should now be cleaned up and fixed.