Release 1.6.0

Fixes
---

- Updated sphinx and docs conf (#400)
- Documented samplers async behavior (#408)
- Added more properties to `MockDWaveSampler` (#403)
- CI refactored; leaner integration tests (#405)

Changes
---

- Dropped Python 3.5 support (#405)

Author: randomir

dwave/system/package_info.py

@@ -14,7 +14,7 @@
 
 __all__ = ['__version__', '__author__', '__authoremail__', '__description__']
 
-__version__ = '1.6.0.dev0'
+__version__ = '1.6.0'
 __author__ = 'D-Wave Systems Inc.'
 __authoremail__ = '[email protected]'
 __description__ = 'All things D-Wave System.'