Update nzbget-testing url

Closes #1015.
Fix ruby native compile

Broken by 47c63baae001fb37956f7a254136877cb4f9cd73
Set minimum Python version for Mercurial
Minimize package sizes by skipping git history
- CouchPotato, Headphones, XDM
Merge branch 'develop' of github.com:SynoCommunity/spksrc into develop