Attempting to fix sqlite threading issues
Log whether DatastoreManager is using an existing directory
Add a UUID to temp folder path generation code

Previously, running tests consecutively that didn't clean up properly
appeared to reuse the temp directory from previous tests. Perhaps
because the test runner reused a JVM.
Fix test using non-threadsafe list in multiple threads
Some threading fixes for database connections:

If a connection is opened on a 'non-main' thread,
we can't close it from the SQLiteWrapper.
Remove commented out code
Bring thread count down to 3, to speed up travis builds
Merge pull request #21 from cloudant/30100-sqlite-busy

Address the issues outlined in case 30100 (see comment the top for details)