from Menu entry

Don't show the icon of checkable items in the menu to avoid being
affected by broken styles.

Task-number: QTCREATORBUG-1173

Reviewed-by: Thorbjørn Lindeijer
Task-number: QTCREATORBUG-865

 - lessens open file handles
 - improves help plugin startup further

Task-number: QTCREATORBUG-337
Reviewed-by: ck

Generic highlighter: Interface for automatic download of available definitions. Refactorings and changes in related parts of the code.

Task-number: QTCREATORBUG-1621
Reviewed-by: ck

Reviewed-by: kh1

Reviewed-by: hjk

This is improving the updating.

Reviewed-by: Marco Bubke
Task-id: QTCREATORBUG-1493

This is needed to suppert inline script function of Qml in the designer

Fixes breakage introduced by 34982c1f.
Task-number: QTCREATORBUG-1612
Reviewed-by: dt

 * Make this more reliable and faster using less code.

Reviewed-by: dt

Fixes a crash when drag&dropping e.g. the WebView element to a file
which doesn't already import the org.webkit package.

Enable correct handling of imports again.
This reverts commit de610cac.

E.g. if the type of the node is 'Qt/Image', version 4, 6, search through
the list of imports to find 'Qt'. If an alias for the namespace has been
defined, prepend this to the element name.

Reviewed-by: Erik Verbruggen

Task-number: BAUHAUS-602
Reviewed-by: Erik Verbruggen

The order of imports does matter, therefore it should also be
represented as a list in the model.

Reviewed-by: Marco Bubke

Task-Nr: QTCREATORBUG-1593