Remove copyright headers

The command used to remove all copyright headers is:

```
find org.scala-ide.sdt.core org.scala-ide.sdt.core.tests -iname
"*.scala" -print0 | xargs -0 perl -p0e
's!/\*.*?Copyright.*?\*/.*?(package)!\1!sg' -i
```

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Don't know if you like that one. I had the idea to remove the copyrights because they are horrible outdated. Do you have an actual one that you want to insert?