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

The idea is that it may be a plugin-provided type. We don't want user
code to be riddled with error markers in that case.

Reviewed-by: Roberto Raggi

Reviewed-by: Roberto Raggi

* Add SemanticHighlighter to QmlJSTextEditor to update the semantic info
  in a background thread.
* Add QmlJS::Check to run semantic checks on qml and js documents.
* Add a check for incorrect property names.
* Fix hoverhandler to show tool tips from extra selections over help
  tooltips.

It is used to evaluate expressions to values.
Done to make room for a real 'check' pass.

Done-with: ckamm

* Support for lookup JS vs Qml
* Bind global variables.

Done-with: ckamm

Done-with: Roberto

Done with ckamm