Fix SpecifiedArgument RedHat AST conversion

Did not account for lazy specifications like

    val => "Hi";

which are also parsed as inline definitions with a synthetic ‘value’
modifier.
Expand SpecifiedArgument test

To catch the bug fixed in the previous commit.
Fix Condition RedHat AST conversion

Was missing switch case for ExistsOrNonemptyCondition.
Expand Condition test

To catch the bug fixed in the previous commit.
Fix Meta RedHat AST conversion

Base metas weren’t properly transformed by the general Meta
transformation.
Expand Meta test

To catch the bug fixed in the previous commit.
Fix Invocation RedHat AST conversion

Did not support named arguments.
Expand Invocation test

To catch the bug fixed in the previous commit.
Fix TypeDeclaration RedHat AST conversion

Did not account for type aliases.
Expand TypeDeclaration test

To catch the bug fixed in the previous commit.
Fix ExistsCondition, NonemptyCondition conversion

Did not account for “synthetic” value modifiers.
Expand ExistsCondition, NonemptyCondition tests

To catch the bugs fixed in the previous commit.
Move completeCompilationUnit to ceylon.ast.samples

It’s also useful for other tests (e. g. a RedHat AST conversion test,
soon to be committed).
Add test for completeCompilationUnit RedHat conversion

This is how I found all those bugs fixed in the last 14 commits.
Editor: Fix relict of #42

The type name and arguments of a qualified type weren’t being copied.
QualifiedType: Fix copy()

This tiny little typo caused the original qualifyingType to be used,
which meant (among other things) that Editor didn’t correctly copy
qualifying types (#42).
Add test for Editor

Tests that Editor does a correct and fully deep copy. Since nodes aren’t
Identifiable, we identify them via additional information that we attach
after the copying.

Tests #42.