Reduce threading
Check for unconnected Bitmessage API
Move tests.

* Closes #275.
Refactor of db_store tests.

* Handle setup and teardown inside class.
* Rename file to match module.
* Use a tempfile rather than a hardoced file.
Separately test operations on unencrypted DB.
Merge pull request #1031 from Renelvon/move_tests

Rename test folder
Merge pull request #888 from hoffmabc/fix-threading

Reduce threading