Removed trailing space; fixed formatting to pass pylint/flakes/pep
Made it work on Linux; fixed docstring, sort of
Updated Linux support to not require sudo for whole script:

* Tidied up OS checking to match python docs
* Updated the linux specific code path to use a tmp copy of hosts and then copy it back. This allows us to only use gksudo for the copy, not the whole script.
Backported cross-platform fix for loading blocklists from kill-donate branch
Merge pull request #9 from dflock/master

I made it work on Linux & Tidied up the code/comments a bit