Revert "Merge pull request #1218 from ditorelo/1213b"

This reverts commit 0d313c1b3e13430e64d60d05d0f681850cbd95c6.
Related to #1218 #1233
Normalize json markers to object #1233
Merge pull request #1234 from rjmackay/develop

Fix json_controller::calculate_center() for both core and sharing plugin