Remove trailing whitespace
Fix #30. There are two issues fixed:
- in ia.py, ia_module.main was being dispatched twice. I think this
is a bug introduced when fixing a merge conflict in commit 379b910954f327669ba1940ee8064c8b610be75d
- in ia_download.py, exit(0) at the end. This appears to be convention
that ia modules are supposed to use, so Sam recommends doing this in `ia download`
as well.
Merge pull request #33 from rajbot/master

Fix bug where `ia download` was attempting to download files twice. See #30