Allow hard-limit target state when homing a motor
X-ray tube base class added
Dummy X-ray tube added
Add X-ray tube tests
Add X-ray tubes to the docs
Merge pull request #346 from ufo-kit/add-xray-tube

X-ray tube added
Add measure decorator to time execution
Add measure unit test
Merge test_expects into test_helpers
Merge pull request #348 from ufo-kit/measure-decorator

Add measure decorator to time execution
Merge pull request #344 from ufo-kit/allow-hard-limit-in-home

Allow hard-limit target state when homing a motor
Add image taking convenience routines

like take_dark_field which closes a shutter and acquires a frame.
Restructure processes tests
Test image taking routines
Turn processes module into a package