Replaced Solium in favor of Solhint (#1575)

* Adding solhint, working on style fixes.

* Upgraded to solhint 1.5.0.

* Removed all references to Solium

* Updated mocks to make the pass the new linter rules.

* Reformatted the .solhint.json file a bit.

* Removed Solium configuration files.

* Remove Solium dependency.

* Add comment explaing disabled time rule in TokenVesting.

* Revert to the old (ugly?) style.

* Revert SignatureBouncerMock style.

* Fix ERC165InterfacesSupported interface.

contracts/mocks/PauserRoleMock.sol

@@ -8,6 +8,7 @@ contract PauserRoleMock is PauserRole {
     }
 
     function onlyPauserMock() public view onlyPauser {
+        // solhint-disable-previous-line no-empty-blocks
     }
 
     // Causes a compilation error if super._removePauser is not internal