Fixes operator== for production properties which didn't take prediction
into account. Additionally added the operator<< with iostream for
unit testing and debugging purposes.
this is just the result of
```
find -iname "*.[ch]pp" | xargs sed -i "s/ *$//"
find opm/parser/share/keywords -type f | xargs sed -i "s/ *$//"
```
so if it causes conflicts with other patches, the others should get
priority. The rationale behind this patch is that some people tell
their editor to remove white space which leads to larger than
necessary patches...
