Generate table name from data file name

[seancolsen]

In the REST API, when we created a table from a data file, the table would be created with a name generated from the file name of the data file.

Now with the RPC API, such tables are created with generic names like "Table 7".

I'd like the tables.import RPC API to be smarter about auto-generating table names. For example, when the data file has a name like "birds.csv", the resulting table name should be "birds".