This patch adds additional API for setting the stroke/fill
properties of vector layers. You can now set/get color, stroke
width and stroke style via the PDB. Pattern get/set API is not
yet implemented.
This patch also updates a missing parameter check for GimpVectorLayer
in gimp_config_param_spec_duplicate (), and adds additional API
in /app to make it easier to safely retrieve GimpVectorLayerOptions.
We now have a proper PROP_VECTOR_LAYER property in the XCF which will
store the various data relevant to vector layers.
This also fixes saving this new type of layers at all, since it was
broken in MR !773.
This patch improves vector layer UX based on feedback.
In summary:
* Makes vector layer editable from the Path tool
* Adds initial PDB for creating vector layers in scripts
* Size vector layers to the path size, rather than image
* Transform tools utilize the path for resizing
* Path tool automatically selects vector layer path
