to QgsNetworkAccessManager, and add a checkbox in the network
logger panel to allow users to temporarily disable the network cache
This can be VERY useful when debugging QGIS network activity, or when
using QGIS to test server side changes.
This is a transient setting only, and is forgotten as soon as QGIS
is closed. That's by design -- we don't want users to accidentally
leave this enabled and cause unnecessary server load.
Move vector, project and network related core .cpp/.h files into
dedicated subdirectories.
An attempt to organise src/core better to make things easier to find.
