Function: addToken(address _token)
Adds a token (LToken) when the number of lending pools increases.
Inputs
_token
Control: Completely controlled by caller.
Constraints: N/A.
Impact: The token address corresponding to the pool added.
Branches and code coverage (including function calls)
Intended branches
Token is added if valid and checkable through
tokenList()
if it is a valid LToken.
Negative behavior
Revert if not called by minter.
Revert if token is already set.