Resolve warnings

This PR solves most warnings reported when compiled with `-deprecation -feature -unchecked -Xlint`. A lot of 2.10 features are introduced, thus the changes finally break backwards source compatibility.

Further changes in scala-ide-play2 and scala-worksheet are required, I'll open the PRs there too.

Most changes aren't controversial. For commit 2004e46 only Exceptions are caught because I didn't saw a point in catching Throwables too. Commit e45ea11 probably needs most attention because it is possible that it breaks behavior.