- GoTest prefix support, for running parallel tests
- Display source code of calling site
- t.LockResource("database", "config-dir"), acquires exclusive access
  to these resources and prevents parallel tests from using them.
- Benchmark support
- Improved logging of multiline strings:

---------------------------------------------------------------------
FAIL: filename:line:TestMethod

... CheckEqual: A != B
... A: <string below>

... A: <end>
... B: <string below>

... B