Game parser/compiler games screen breaks

The compiler/parsers fail to record the `---` between exercise screens if it's not appenede by a newline:

Doesn't work:
```
---
## Game content

question
%exp
...
%
---
question
%exp
...
%
```

Works:

```
## Game content

question
%exp
...
%

---
question
%exp
...
%
```