 Issue #1169264 by dalin: System main block does not respect context assigned weight when block module is enabled. Fix makes context block reaction honor weight settings of blocks already present in region when adding blocks.
 Issue #1169264 by dalin: System main block does not respect context assigned weight when block module is enabled. Fix makes context block reaction honor weight settings of blocks already present in region when adding blocks.

oddhill/context,oddhill/context