added download_file_list tool (needed for at least UKIDSS, fermilat)
completely download_file_list code filename namer; it's a bit complex
but I think rather useful
added data utils import
added example in docstr
bugfixes (actually ran the test example)
Fix imports and add __all__ for download_file_list
Merge pull request #2 from cdeil/file_list_downloader

Fix imports and add __all__ for download_file_list
Merge pull request #69 from keflavich/file_list_downloader

(fits) File list downloader