TST: Use temporary directories rather than assuming /tmp
TST: Use tempfile in test_feature tests
TST: Clean up parent temporary directory
TST: Use tempfile directories in test_multiconxn
TST: Use tempfile directories in test_schema
TST: Use the standard tempfile temporary directory in test_layer
Merge pull request #67 from kjordahl/test/tempfiles

Use tempfile package instead of writing to /tmp