Update 0.6

Added an engineer with a MAC-10 submachine gun for the side of the rebels, now you can build fortifications in skirmish mode;
Skirmish mode and AI have been slightly reworked;
Some sprites of buildings and units were redrawn;
Added new smoke and fire effects;
Added sound effects and music;
PMC engineer now has a Mossenberg 500 shotgun
Removed Molotov cocktail thrower due to inefficiency.
Game interface changed
The need for provisions has been removed;
Minor bugs fixed.