compensate for lazy-loaded associations using proxy classes.

So, when an Entity is loaded and you try to convert it to an array, it can be a problem if you have associations in that Entity. It will cause errors like

```
[29-Jan-2013 19:13:55] PHP Fatal error:  Call to undefined method DoctrineProxy\__CG__\Dizkus_Entity_Topic::get_entityPersister() in /Applications/MAMP/htdocs/core.git/src/lib/Zikula/EntityAccess.php on line 76
```
because the properties of the __Proxy__ are attempted to be converted in the Array. This is impossible since there are no `getters` for the proxy properties. 

This PR attempts to correct that. The double check `(if instanceof and if name)` may be overkill. Probably just `if (name)` would work, but just being thorough :smile:

| Q             | A
| ------------- | ---
| Bug fix?      | kinda
| New feature?  | kinda
| BC breaks?    | [no]
| Deprecations? | [no]
| Tests pass?   | n/a
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a