Pass right prototype to SeqLiteral elements.
Better typing of seqLiteral in erasure.

Fixed two problems with previous commit.
Fix by-name arguments

Previous scheme relying on Attachments was fragile. We now use
a dummy method application, which transmits info reliably to
Erasure.
Merge pull request #267 from dotty-staging/fix/byname-args

Fix by-name arguments
Remove Separator. It's not used anymore
Call getClass 30 times less in TreeTransforms initialisation.
Precompute initial NXTransformations in TreeTransforms.

Helps Annotation transformers which do not need to reinitialise themselves anymore.
Make TreeTransform type check in dotty. There's no magic type behind getClass in dotty.
Phases: The operator <= does not need a context anymore
Phases: set the period correctly
Changed erasure of ThisType

Was: erasure of underlying type.
Now: erased typeRef of underlying class.

The differ if there is a self type. In this case,
a this type did erase to teh erasure of the self type, which
is wrong.
Fixed narrowLiftedOwner in LambdaLift

A lot of cases were missing before and caused failures
in the newly added test in TreeChecker#typedThis.

Now we assure that all this references appear inside
the referenced class.
Merge pull request #265 from dotty-staging/fix/type-seqliteral

Pass right prototype to SeqLiteral elements.
Merge pull request #274 from smarter/fix/period-of-phases

Phases: set the period correctly
Fix subtyping of null and refined types.
Drop NotNull class and associated code.
Fix #248: Class cannot inherit from refinement types

We now check that classes do not inherit from refinement types
(unless they are an encoding of parameterized types), nor from
& or | types.
Remove obsolete mentions of the NotNull class
One more test case, coming from #214.
Fixed test