v0.0.0.74 - Wall connections and colours

We've made a colour change to our walls and floors. We've gone darker for a more industrial look.  Have started connecting the walls up when built,  which gives a less blocky appearance to the walls.  What do people think?

Fixed a crash if you deleted a mining unit whilst a worker was picking up.

Added 'Z' key to open all doors (internal, then external) &  'X' key to close all.

May also spot that we've updated our battery item image, and it now has room to display charge level. Will be adding that.

Nick