i3blocks-1.5-bp156.3.6

- Drop pandoc BuildRequires: does not exist on all archs and seem
  unused.

- Update i3blocks to version 1.5
- Set sysstat as recommends as sysstat is buggy and not a hard
  requirement (depending on user configuration)

- Replace future aims, and ensure neutrality of description.

- Fix build on Leap 42.3

- Initial package