LSS Zone 1.2.0 alpha 1

New:
- 'pick internal point' mode added to 'LSS Zone' tool (it launches
tracing of a contour, which surrounds picked point)

Fixes:
- query string editing finally works well (carret position properly
restores after changes)
- custom attributes remain attached after zone's contour editing using
'LSS Zone' tool
- SU crash after deleting a nodal point while 'LSS Zone' tool is active
is fixed