Allow for dynamic table names.

This adds a toString() call to the TableName parameter when sending a request to Dynamo. This will allow the table name to be either a string, or anything that will output a table name as its toString output. For example, we are using a table class that allows us to generate prefixes based off of the environment settings (_test_table), and also suffixes for our time-series tables (table_0314).

This may not be the right way to go about this, but it was the simplest and didn't break anything that I could see.