The CHOICE representation in ASN.1 Value Notation was incorrect: there
is no need for curly brackets.

The PrintAll-related function was returning the enumerated integer
instead of the enumerated value (string).

For each type a new function that computes the string of a variable in
the ASN.1 Value Notation format (GSER) is generated in the Python A
mapper. This function is now used by the PrintAll function, when
displaying a variable. The GSER function can be called independently
from the print statements, and can be used for example by the
auto-generated GUIs to log data.