Constants dock should reflect current decimal separator instead of always dot

[Former user]

Originally reported on Google Code with ID 82

The decimal separator in the constant values should be set accordingly to
the settings.

Reported by helder.pereira.correia on 2007-07-22 03:05:47

[Former user]

``` Forgetting this for now since the important is that the decimal separator is now set correctly ater clicking the constant and inserting it into the expression input box (see Issue 66). So I'm shifting it for 0.9. ```

Reported by `helder.pereira.correia` on 2007-07-22 22:20:52 - Labels added: Milestone-0.9 - Labels removed: Milestone-0.8

[Former user]

Reported by `helder.pereira.correia` on 2007-11-03 19:43:06 - Labels added: Milestone-0.10 - Labels removed: Milestone-0.9

[Former user]

``` Partially implemented in trunk revision 989. It only misses to handle the on-the-fly changing of decimal separator. ```

Reported by `helder.pereira.correia` on 2008-01-14 02:54:56 - Status changed: `Started`

[Former user]

``` Fixed in trunk revision 990. ```

Reported by `helder.pereira.correia` on 2008-01-14 22:50:33 - Status changed: `Fixed`