v0.0.0.40 - Workers and Mining

Well it's been a couple of weeks, but i now have workers and mining added!

Workers now visit each tile you wish to be constructed, and take x amount of time to build, and likewise to destroy. They are very dumb at the moment though, as build orders just go into a list and an idle worker just grabs next in queue. will need to take into consideration distance and priority at a later date.

Mining unit has been added, which provides a mining unit. This now heads off to an asteroid belt i've added (to the left hand side of the play area currently) and starts mining (quite enjoyed playing around with mining laser effect!). Very much liked playing around with particle effects, you may notice now that my solar connectors glow when powered, and workers have a 'welding' effect when building/destroying. 

Now at a point when i need to figure out how to deal with storage, once i've got a grip on that and add a refinery i might actually have the beginnings of a game, rather than just some prototype game mechanics!