Added several mysqldb functions:

* soft deletes
* instance_destroy

There is the start of a select() function, not sure if we should go that
route or kill it.

Lots of TODOs to fill in still.

Change-Id: I9e8f1bb7452417cc8e9482127826d8e496c3a36d
Merge pull request #7 from bdelliott/flesh_out_instance_destroy_and_update

Added several mysqldb functions: