Construct buffs.

-Juggernaut's force wall duration increased to 20 seconds (it was 5 before which was completely useless)
-Artificers gain a new spell Lesser Magic Missile - which functions as normal MM but with a significantly longer cool down (purpose of it is to give builders a chance to get away, or provide supportive fire in a construct spearhead)

-Juggernauts now have ablative shells, which means that energy projectiles will be deflected as with ablative vests, as with vests slug throwers aren't affected
Merge branch 'master' of https://github.com/tgstation/-tg-station into reflectivejugs
-Changed the weighting on Juggernaut's shell to make it more likely to deflect the energy projectile than reflect it.

For Lesser Magic Missile:
-Halved the projectile life span
-Added a cap to the amount of targets, 6 as an experimental number

-Made the helper text more useful for new constructs
Merge pull request #997 from Malkevin/reflectivejugs

Construct buffs.