[[ ImageMetadata ]] Implementation of export with density metadata
Merge commit '391b48f67a92283a10dc96f87b1d34386fd8a91a' into feature/export_image_metadata
[[ ImageMetadata ]] Some changes to allow with effects to be optional when with metadata is used and improvements to the png density handling
[[ ImageMetadata ]] Added documentation for export image with metadata. Changed location of syntax to just before file/container parameter. Moved code outside of snapshot specific code so metadata can be used with all three export commands. Fixed bug with export <format> style image export where it wasn't setting the image format.
Merge branch 'feature/export_image_metadata' of https://github.com/montegoulding/livecode into feature-export_image_metadata
[[ ImageMetadata ]] Moved metadata array evaluation to MCExport::exec to ease merging with 7.0.
Merge branch 'feature-export_image_metadata' into develop