Merge branch 'master' into defaulttypeargs

Merged ExpressionVisitor

Conflicts:
	src/com/redhat/ceylon/compiler/typechecker/analyzer/ExpressionVisitor.java
don't check variance of unshared members fixes #375
check that members accessed on other instances are def initialized
Merge branch 'defaulttypeargs'
Merge branch 'defaulttypeargs' of https://github.com/ceylon/ceylon-spec into 533
Merge branch 'master' of https://github.com/ceylon/ceylon-spec into 533