Feature Request: Attach

[gjrtimmer]

unqlite is considered to be the nosql counterpart of sqlite.
There are however some features available within sqlite which I also would like to see in unqlite.

Feature Request: Attach

Implementation of a attach method. This attach method will take a filepath as argument.
It will attach the provided filepath to the current database connection.

This allows to use a single database connection to interact with multple unqlite files. Also it might allow JX9 selection over collections in multiple unqlite files.