add BC alias array keys for modvars. refs #1313

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #1313
| Refs tickets  | -
| License       | MIT
| Doc PR        | -

@cmfcmf - is this sufficient?

@drak - should this block be wrapped in a legacy check? I can't ever remember how that is used or why. Since `Zikula_View` is legacy/deprecated maybe it doesn't matter anyway. If this is alright then go ahead an merge it and close #1313