better operator type inference with anon types

Conflicts:
	src/com/redhat/ceylon/compiler/typechecker/analyzer/ExpressionVisitor.java
ProducedType: forward underlyingType and isRaw info to resolvedAliases
prevent aliases being defined recursively to fix #524
Conflicts:
	src/com/redhat/ceylon/compiler/typechecker/model/ProducedType.java
Merge branch 'master' of https://github.com/ceylon/ceylon-spec
fix #530 by relaxing type constraint checking on types that appear in
is conditions (we can relax more syntactic positions later) 
Conflicts:
	src/com/redhat/ceylon/compiler/typechecker/analyzer/ExpressionVisitor.java
quickly fix the test
support for native annotation #348
Merge branch 'master' into defaulttypeargs

Merged ExpressionVisitor

Conflicts:
	src/com/redhat/ceylon/compiler/typechecker/analyzer/ExpressionVisitor.java