Uniqueness on insert is now determined by the hash of some columns stored in one new column with an unique index. This is more efficient than letting MySQL handle compund uniqueness of more columns
Fixed bugs in mysql migration command and added method for inserting to mysql using given connection
(cherry picked from commit 1b5a3b9)
Fixed a bug where questionnaires with no human_readable_question or human_readable_answer would throw an exception
(cherry picked from commit 68b2a08)
Changed the way uniqueness is calculcated. Also fixed a bug where mysql_wrapper wouldn't log correctly.
(cherry picked from commit 58bb014)
Changed logging level to debug.
(cherry picked from commit 6bb82ad)
Added log file for migration
(cherry picked from commit 00b5b26)
Merge branch 'devel' into mysql

Conflicts:
	sensible_data_service/db_access/mysql_wrapper.py
	sensible_data_service/utils/db_wrapper.py
Fixed a bug in mysql wrapper where an exception would be thrown if no where constraints were used