Redesign level venture capital to prevent attacks from other players

[StillFantastic]

If some players send ethers to addresses of future instances could lead to other players unable to win.

cypherpunks-ctf/contracts/levels/VentureCapital.sol

Lines 14 to 15 in aa4c250

	if (msg.value > 0 && address(this).balance == 1 ether) {
	developerMode = false;