Task-number: QTCREATORBUG-3071
Reviewed-by: Erik Verbruggen

It still generates too many false-negatives for now. Will be enabled
once the remaining lookup failures have been fixed.

Reviewed-by: Erik Verbruggen

Reviewed-by: Erik Verbruggen

Link now caches imports. That means importing the same library (say, Qt)
from more than one file no longer creates an importing namespace for
each one. Instead, a single one is created for the instance of Link.

To make this work, the type environment in ScopeChain has been given its
own type: Interpreter::TypeEnvironment. That has the added benefit of
being able to carry meta-information about imports. You can use
TypeEnvironment::importInfo(qmlComponentName) to get information about
the import node that caused the import of the component.

Reviewed-by: Roberto Raggi

* If possible, create LookupContexts through SemanticInfo; it caches the
  linked Context and will be faster.
* Contexts now own their Engine.

Reviewed-by: Lasse Holmstedt

Reviewed-by: ckamm

Reviewed-by: ossi

Reviewed-by: Erik Verbruggen

Task-number: QTCREATORBUG-1439

Done-with: Erik Verbruggen

Use ScopeBuilder.push(...) for the same functionality.

Reviewed-by: Erik Verbruggen

Task-number: QTCREATORBUG-1021
Reviewed-by: Erik Verbruggen

Avoids bug where import errors would show up in all files.

Reviewed-by: Roberto Raggi

Task-number: QTCREATORBUG-874
Reviewed-by: Erik Verbruggen

* Fill the snapshot with files that could be imported.
* Implement package imports.

* The qmldir file is not parsed yet.

Reviewed-by: Erik Verbruggen

Reviewed-by: Erik Verbruggen

All files have been renamed from Qml to QDeclarative

Done-with: Erik Verbruggen

Done-with: Erik Verbruggen

Just the declaring member isn't enough.

Instead of only maintaining a flat list of scopes, actually store the
global, component chain, root object, scope object, function, id and js
scopes separately.

Done-with: Christian Kamm

And made the warnings/errors translatable.

This now errors for:
anchors.undefinedAnchor: foo
x.undefinedAnchor