Nyall Dawson 0cdad2307b Add api to allow reading a QgsProject file without loading any layers
This causes the project to be read, but no data providers created for
layers (i.e. the same result as loading a project in the app and
choosing to leave bad layers in the project).

It's intended for occasions when you want to efficiently access properties
of a project without the (often very expensive) cost of actually
loading layers. E.g. to just read project metadata, parse the
layer tree structure, extract print layouts or renderer properties, etc.
2019-07-10 08:10:49 +10:00
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