LSS Zone 1.1.0 alpha 3

- 'undo' of all batch operations works as expected now ('stand_alone'
optional parameter added to all methods where @model.start_operation is
available and if it set to 'false', then method does not perform
@model.start_operation)
- hanging of 'Zone Tool' dialog issue of previous alpha version is fixed
- faces inside zone elements groups now placed on 'LSS Zone' layer
- 'cut openings' part of 'Zone Tool' dialog now appear only when 'room'
zone selected (does not appear, when 'box' or 'flat' zone types are
selected)
- 'Zone Tool' dialog now aware of selected zone type (appropriate radio
button clicks automatically after zone selection)