Fixed issue 2479 and made imported links absolute 

efiction chapter downloader would keep getting multiple identical chapters, which occurred on multiple efiction sites
also improved tests
also made imported links absolute to the original site (since they definitely wouldn't work on ours without editing anyway).

Fixes: 
https://code.google.com/p/otwarchive/issues/detail?id=2479
https://code.google.com/p/otwarchive/issues/detail?id=3898

Signed-off-by: shalott <shalott@gmail.com>