fixed pl/com bug, file name format changed

Changed the domain from .pl to .com which led to no downloads!

Add new feature to avoid downloading multiple accepted solutions for
same problem!

Some more work to do :
1. Choosing only the best solution to download (based on time, memory)
2. Get the full problem name instead of just problem code as the file
name

Few other ideas: A browser extension for chrome/fire-fox to automatically show a ("solve") button on all spoj questions clicking which makes a file in desired language with pre-defined template (like header-file etc) and then open that file with IDE by passing command line argument to the IDE.