WWVegas headers are not correctly included always

WWVegas headers are not correctly included always.

For example
```
#include "wwdebug.h"
```
should be
```
#include "WWDebug/wwdebug.h"
```

The former works on some projects because they make WWDebug & Co an include directory, but not all projects do this, so it can fail on some.

We need to remove all WWVegas subdir include directories and then fix the paths in source files.