refactor some code
fetch next page and download all images available
Merge pull request #13 from aggrolite/refactor-and-support-pages

Refactor and support pages
Added code to prevent re-downloading files. Thanks to @mgsk for the code.
Added inital support for scraping usernames in addition to subreddits. At this point multiple usernames don't quite work right. Updated README.md to reflect this. Added GetOpt::Std and support for --help and --verson.
README.md formatting.
Accidently left some debugging code in.
Added support for limiting the number of images to download per subreddit/user. Edited usage and README.md accordingly.
Added ability to download from a search. Updated README.md with info on this and a Bitcoin donation address.
Fixed placement of QR Code on README.md
Fixed #16 by using typal@aa71e73. Also implemented a user string per
the reddit API rules.
Forgot the version string in VERSION_MESSAGE.
issue #11 - create subdirectories for each imgur album

this change also includes a fix for album extraction as imgur's
json structure changed just enough to break our code