Sql persistence updates to add non numeric data types

This is an initial commit of the SQL persistence service with support for non-numeric data types. It should support persistence of all types.

It has been tested by a number of people. See issue below.
https://code.google.com/p/openhab/issues/detail?id=441

Note that there is still some work to do on the query. This works fine for numeric data types, but may need conversion for other data types. I'll look at this in the near future but I think it's worth getting the storage side into the main snapshot.