file-level blacklist for lgogdownloader

The idea for this came with witcher 2  - I wanted to be update it without downloading redkit editor too. I don't mind few MB of worthless extras in my archive, but 6 GB was too much. Help for the blacklist is available in man page. I may have overengineered the syntax a bit, I thought I'll leave space if someone later wants to implement simple glob matching or add more flags. I actually have an idea for one additional flag, but I still need to think if it's the right solution... Blacklist works well enough and can be merged as it is now.

The patch slightly depends on c++11 (auto typed variables, std::move), I'm not sure what policy you have on this, I can rewrite it without those bits if you want.