BUG #14466: Fixed calculator panel.

Added ability to pqLineEdit to disable resetting of cursor position on editing.
We had added support for that to show most significant digits in numercial
line edits. That was causing problems with calculator. Calculator now disables
this cursor-resetting on the pqLineEdit instance.

Change-Id: I99593371e80dd2e64648b2b9f0e78ec3534df8c8
Merge topic '14466_fix_calculator_panel' into next

e918236 BUG #14466: Fixed calculator panel.