I know what the filter does, but I don't see why it's there (security?).

The Python script that `modulecmd.tcl` spits out, includes other stuff too, e.g. an `os.unlink('<script>')`, to automagically remove the script on execution. If we filter that out, all the `/tmp/modulescript_...` will stay when they're triggered from within EasyBuild.
Also, environment variables are undefined with `del os.environ`, which are also kicked out with this filter... That's incorrect, plain and simple (an empty env var is not the same as it not being there).
```python
os.environ['EBROOTTOY'] = ''
del os.environ['EBROOTTOY']
```

After thinking about this when writing this remark, I now realize it's there as a kind of security measure (is it?). 
But it only works within an EasyBuild session, if people run `module load` outside of EB, they're still vulnerable, so what's the use...

In any case, if you feel this should be put back in place, we need to allow `os.unlink` and `del os.environ` too, and maybe more stuff (although I can't think of something).