v0.0.0.106 - Mining laser / salvage improvements

Few more refinements with tractor beams, salvage depots and mining lasers.

• Mining laser now has an on/off switch, and can see it's range. Helpful to see range to see which salvage depots are usable.
• Meteors now damage salvage depots unless in a tractor beam and being moved under control into them.
• Show asteroid belt tractor beam  area. Not sure if i made it clear that if you place a tractor beam near asteroid belt, it would be able to grab asteroids from it. 
• Added a help page. Just some initial info at the moment, but now have a place to keep adding info as i go.
• Have removed a couple of lowest res support. Lowest is now 1080x720. Was getting tricky with text size/formatting. If people do want lower res support, let me know. It is possible to put it back in, but will just need more work to correctly implement text resizing. 

Next up, i think a good idea would be to make the start location of you ship be selectable on start of game. This gives a bit more variety, as from the off you can decided to start near asteroids to use tractor beams, or stay further away (and safer). This also means i can drop large  stationary asteroids over the map, that could again influence where best to start.     

Happy new year all!

Nick