Stop running phases after errors were encountered
Reset frozen for transformed class denotations.

... so that we can add new members to transformed class denotations.
Merge pull request #71 from odersky/fixes-for-transforms

Fixes for transforms
Reorg of info transformer framework
Renamings TreeTransformer -> TreeMap, TreeMapper -> TreeTypeMap

This makes naming uniform between trees and types, and also avoids the clash with
transform.TreeTransformer. The idea is that transformers are parts of phases, and
have logic that is phase-specific. In particular, a context is passed around when
transforming a tree. Maps are simpler, they only have a T -> T apply method.
Renaming core.Transformer(s) -> core.DenotTransformer(s)

To bring in line with TreeTransformer terminology.
Refactored denotation transformers

Many small and large changes. Added samplePhase to demonstrate functionality.

To test functioning, run the compiler with args

     tests/pos/uncurry.scala -Ylog:sample,terminal
Re-enabled and renamed tests

CreateCompanionObjectTests were re-enabled. They failed in a previous version but succeed again in the latest commit.
Also uncurry.scala got renamed to curried.scala.
Merge remote-tracking branch 'odersky/topic/info-transforms' into LazyVals

Conflicts:
	src/dotty/tools/dotc/Compiler.scala
wip on lazy vals