MSC: Fix parsing nested ans1 sequences in .msc file parsing
The MSC parser is unable to parse for example:
instance TASTE_System;
out bbbbb({ Coordinates { x -1, y -1 }, Pixels { { empty, empty, empty, empty }, { empty, empty, empty, empty }, { empty, empty, empty, empty }, { empty, empty, empty, empty } } }) to player;
endinstance;