In preparation for caching Contexts.

Reviewed-by: Erik Verbruggen

Task-number: QTCREATORBUG-1757

By actually storing the documents instead of only the root and id
environments.

Filtering them out has long since become unnecessary. It was used back
when JS files were sourced from Script elements - there they'd only
make the functions available. Now functions and variables are imported.

Task-number: QTCREATORBUG-1735
Reviewed-by: Erik Verbruggen

The type information is now generated at runtime.

Task-number: QTCREATORBUG-1021
Reviewed-by: Roberto Raggi

Such as
property int foo: bar
property int bar: foo.

Task-number: QTCREATORBUG-1389
Reviewed-by: Roberto Raggi

Reviewed-by: Roberto Raggi

Reviewed-by: Christian Kamm

* Context::build was potentially dangerous. Link and ScopeBuilder
  went out of scope before their results stopped being used.
* ScopeBuilder: If no function scope object was found, don't add it.

Reviewed-by: Erik Verbruggen

Reviewed-by: Erik Verbruggen

Done-with: Erik Verbruggen

Done-with: Erik Verbruggen

This used to contain all functions declared in Script blocks. With them
gone, there's no reason to keep it.

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

Done-with: ckamm

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

* The qmldir file is not parsed yet.

Reviewed-by: Erik Verbruggen

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

* 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.