UnitTest: Tensor-src-tizensensor / Initial test cases

UnitTest: Tensor-src-tizensensor / Initial test cases

1. Unit tests are added.
2. dummy_sensor.c/h offers dummy Tizen sensor framework for unit tests,
where we cannot activate Tizen sensor framework daemon.
3. Bugs were found with the unit tests and they are fixed.
    - g_hash_table misuses
    - property configuration errors
    - frequency (framerate) handling
    - Clean up and configured-status handling
    - Mutex deadlock
    - Timestamp handling

Changes v1->v2:
- Use G_USEC_PER_SEC for readability, suggested by dongju.chae@samsung.com
Changes v2->v3:
- Added error-clear in testcase, suggested by dongju.chae@samsung.com
- Removed unnecessary code (residue of internal tests), suggested by jy1210.jung@samsung.com
Changes v3->v4:
- Added free ops for pipelines, removed duplicated codes, suggested by jy1210.jung@samsung.com

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>