Update to v2 (After game jam end)

Updates

• More energy generated per second
• After depletion, energy restores faster
• Energy is now regained whilst waiting for reset
• All turrets are deactivated when energy is depleted
• Electronic voice informs player on energy depletion, energy restoration, and defeat
• Main base takes four times the energy of a normal turret, rather than twice
• Energy bar has half-way mark marked
• If energy is less than half, upgrade buttons are dulled out (they become transparent and do not highlight when player mouses over)
• Some balancing changes made to enemy spawn time - it's a bit easier in the beginning but ramps up to very difficult quite quickly
• Music made quieter
• Credits fixed and updated