fix autoload-dev example for PSR-4

The example leads to the following error.

```
  [InvalidArgumentException]
  A non-empty PSR-4 prefix must end with a namespace separator.
```
Merge pull request #2942 from havvg/patch-1

fix autoload-dev example for PSR-4
fixed class map generator when using a heredoc with spaces
Merge pull request #2945 from fabpot/classmap-hotfix

fixed class map generator when using a heredoc with spaces
Ignore classes in ClassMapGenerator