[#642] Add spaces to log messages where they are missing
[#642] Use has_table_privilege and has_schema_privilege instead of experimental privilege checks.

Conflicts:
	ckanext/datastore/plugin.py
[#642] Make check functions consistent (return bool instead of raising exceptions)
[#642] Refactor datastore plugin configuration, improve (and fix ;-)) tests
[#642] Fix how the check for separate urls is ignored in legacy mode.
I put the check for the legacy mode in this function to make it testable.
[#642] Simplify check for debug mode, only create _foo once