This file, specified with the keyword mastertex in the test description
file, holds all the macro definitions for the formatting of the exams.
Manyex writes the calls to these macros in the right places of the exam file,
and the macros have to be defined in the mastertex file.
Manyex also defines macros to act as counters for exercises and questions.
These are directly defined by Manyex and can be used in the
mastertex macros, as shown in the example below. Most of them are
required, even if empty, for instance
\newcommand\mnglobalheader{}