'java.lang.String com.activeandroid.TableInfo.getTableName()' on a null object reference

With this code, the problem persists.
```
<meta-data
    android:name="AA_MODELS"
    android:value="com.myapp.model.Item, com.myapp.model.Category" />
```
Then I found that by removing the space, it worked
like this
```
<meta-data
    android:name="AA_MODELS"
    android:value="com.myapp.model.Item,[No space here]com.myapp.model.Category" />
```