Started migration to new Scala 2.10 Type Tag API.

Hi,

As Manifests will become deprecated in the coming version of Scala, we should migrate them to new Type Tag API [1]. As a bonus we got really sexy and neat `ClassTag` syntax, instead of the manifest implicits boilerplate.

I've migrated some classes from manifests to `ClassTags`. New code looks much clearer.

If you merge this pull request to the master, I'll handle the migration of the rest of the code base in coming weeks.

Thanks for @aloiscochard for friendly reminder that we should start the migration effort.

Cheers.

[1] http://docs.scala-lang.org/overviews/reflection/overview.html