Fixed: Saw CShell.CheckShell.138: erroring out on "Null object", added appropriate handling.
Fixed: Do not call RRDTool.UpdateRRD multiple times for devices with multiple values that have RRD enabled.
Fixed: Increase replace limit of Events.ReplaceDeviceVar from 10 to 999. Fix for issue #520.
Merge pull request #34 from danfos/minor-fixes

Minor fixes
Changed: Append _id to certain scenario, heating and constant columns
Added: JSON-RPC supports OPTIONS method
Fixed: JSON-RPC will return "host:" header if present in POST/PUT request
Added 'SendCommand' support to ELVMAX. feel free to test
Fixed: Install SQL couldn't be loaded, keyname was missing
Fixed: SQL settings_jsonrpc integer values will be always set to 0
Fixed: SQL Upgrade 1.0.019 to 1.0.020 contained errors