not working yet, just set the menu entries
QgsMapLayerStyle::StyleCategory has moved to QgsMapLayer to avoid making QgsMapLayerStyle a QObject and they are mostly used in QgsMapLayer
* create QgsMapLayer::LayerFlags for Searchable, Identifiable and Removable
this brings back the information previously saved in the project node back to the layer node
this will allow to embed this information in layer styles
* skip unexisting flag node to avoid setting wrong value for flag
* mark QgsProject::(set)requiredLayers as deprecated
* better API docs
* use new API in current code
* more docs and more old API fixes
* fix bad conversion
* more old API fix
* add missing SIP_OUT
* s/testFlags/testFlag
* fix var name
* adapt project test to test flags
* remove debug calls
* fixeS
