Alba 1.3.16

important: Alba 1.3.16 requires Arakoon 1.9.18

Bugfixes:

• C++ client: fix hang of rora request ( #719 )
• make sure blob cannot be destroyed prematurely ( #721)
• allow older gcrypt for challenged distros ( #720 )
• maintenance agents cause NotMyTask on restart ( #696 )
• log & die when negative disk usage detected ( #209 )
• LRU redis eviction ( #690)
• consider removal of broken objects ( #730 )

Various:

• no longer use janestreets's repo ( #731)
• robustify stress2 ( #715 )
• more functions are tail recursive ( #717 )
• cleanup a few todos ( #727 )
• nsm host statistics with --to-json ( #729 )
• less dropping of abm connections ( #718 )