Doesn't check contracts in other folders

[Jason Du]

I separate contracts into separate folders. Looks like imports from other folders don't work.

HeroCreation.sol:3:1: Error: Source "HeroGenerator/HeroGeneratorInterface.sol" not found: Unknown exception in read callback.
import "./../HeroGenerator/HeroGeneratorInterface.sol";
^-----------------------------------------------------^
HeroToken.sol:4:1: Error: Source "ERC721/ERC721Token.sol" not found: Unknown exception in read callback.
import "./../ERC721/ERC721Token.sol";
^-----------------------------------^
HeroData.sol:3:1: Error: Source "AdminAccessControl.sol" not found: Unknown exception in read callback.
import "./../AdminAccessControl.sol";
^-----------------------------------^
HeroData.sol:4:1: Error: Source "node_modules/zeppelin-solidity/contracts/math/SafeMath.sol" not found: Unknown exception in read callback.
import "./../../node_modules/zeppelin-solidity/contracts/math/SafeMath.sol";