Small Fixes

Added some scripts and functionality to Grassy Field so that now NPC can
lose life and heal itself with word gems. If NPC health is below 4, it
will seek out a gem to heal itself.

Bug Fixed - Word Gem was giving NPC two hit points instead of one. It
was a collider issue. Two colliders on NPC causing OnCollisionEnter
function to be called twice.

Also organized some scripts into folders.