[Retros] Add units: 17th update (1NA)

[Mu-Tsun Tsai]

Here's another attempt on the 1NA problem. It also has 15 units, but the 
number of heavy officers have reduced from 1Q+3R to 2R.

Diagram:
http://www.janko.at/Retros/d.php?ff=8/PP6/PBB5/1N6/8/P1P5/kPPK3P/2RR4
(14+1)

Stip: Add the missing unit(s).

Intended solution: +wNb1


Hope it works!

Mu-Tsun