Locking the names of the regression variables and of the calendars

[palatej]

The user is able to define regression variables and to refer them in some specifications by their name. If the name is changed afterwards, the link between the specifications and the variables will be lost, leading to mistakes that cannot be easily identified.

We will use a locking mechanism that will prevent the problem (the user will not be able to change the name of a variables that is used elsewhere in the workspace.

[palatej]

Complex issue. Workload: 20 days