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.
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.
fix stripTypeVar to handle AnnotatedType transparently
fix dealias to handle AnnotatedTypes transparently
add stripAnnots method to Type to unwrap AnnotatedTypes
handle AnnotatedTypes transparently in Tree.denot
Make sure the period of a context always contains a single phase

Multi-phase periods mean that ctx.phaseId is no longer valid, which means
a lot of invariants break.
Ensure that transformStats is run at phase thisTransformPhase.
Make sure AnnotationTransformers run at own phase
Change treeTransformPhase for SyntheticMethods to new default
Change phase handling in enteredAfter

This makes it more consistent with related methods ensureFreshScopeAfter,
installAfter.
Make Literalize run at new default phase thisTransform.next
Change default treeTrannsformPhase to phase.next
Eliminate GettersSetters

Has been replaced by Getters, but some traces remained.
Remove fruitless overrides of treeTransformPhase

Now the default phase of treeTransformPhase is phase.next, we
can remove all overrides that specify the same phase.
Merge pull request #284 from olhotak/pr-annotatedtypes

fixes to handle AnnotatedTypes transparently like the types that they wrap