store allType in a list rather than a map index by kotlin class.

[adminfairjungle]

Allows reusing the same kotlin type (with a different name attribute) in a gql type and a gql inputType.

Avoids many useless kotlin type duplication to circumvent GraphQL constraint that output types cannot be input types (even when it's totally legit).

Example use :

val schema = KGraphQL.schema {
    inputType<MyKotlinType>() {
        name="TypeAsInput"
    }
    type<MyKotlinType>() {
        name="TypeAsObject"
    }
}

[coveralls]

Coverage increased (+0.2%) to 88.08% when pulling 2dfc9d5 on Bertrand:same_type_used_for_object_and_inputtype into 42fef4a on pgutkowski:master.

[adminfairjungle]

Sorry, messed up with my github accounts. Closing the PR. Will reopen it.