For the paranoidClause function, prevent that deletedAt is overwritten w...

...hen the where option is an array

```
db.Guide.find({       
    where: [
        'UPPER("user"."slug") = UPPER(?) ' +
        'AND "user"."deleted_at" IS NULL ' +
        'AND "guides"."deleted_at" IS NULL ' +
        req.params.userSlug,
    ],
    include: [ 
        { model: db.User, as: 'user' },
    ],
}).success(function(guide) {
```
This snippet fails with this error : 
error: column reference "deleted_at" is ambiguous

because paranoidClause adds at the end of the query:
```
AND "deleted_at" IS NULL
```

This pull request first verifies if a deleteAt has been specified when "where" is an array and prevents to overwrite it.
Secondly it adds the tableName to the WHERE clause to prevent this error: "column reference "deleted_at" is ambiguous".