[development] Extend database abstraction layer, to include table creation

[Khalid B]

> 2. Execute a query that will return exactly one column of one row, and return
>    that data value as a simple variable of mixed type.
>
>    Example use case: SELECT COUNT(*) FROM {node} WHERE type='story';
>
>    Suggested function signature: $mixed = db_query_value($sql [, $params])

We already  have this:

http://drupaldocs.org/api/head/function/db_result