migrates to 2.11.0-RC1
Scala 2.11 compatibility.

- Convert \0 to \u0000
- Change TupleClass handling in SlickBackend
- add explicit bounds on existentials: bound inference via
  SI-1786 is compilation order dependent!
- comment out part of a test that currently gives a type
  error.
Merge remote-tracking branch 'xeno-by/palladium0' into tmp/2.11-compat-2

Conflicts:
	slick-testkit/src/test/scala/scala/slick/test/direct/QueryableTest.scala
	src/main/scala/scala/slick/model/codegen/AbstractSourceCodeGenerator.scala