Merge remote-tracking branch 'Greg/development' into development

Conflicts:
	PartPreviewWindow/View3DTransfromPart.cs
Did not mean to check in the conflict.
We now send the right info to MatterSlice when printing a multi material part.
Adjusted touchscreen layout reload behavior.
Merge branch 'development' of https://github.com/MatterHackers/MatterControl into development
Save 'save as' meshes as amf.
Merge branch 'development' of https://github.com/MatterHackers/MatterControl into development
Putting in location where the n extruder heat setting will go.
Put in an ExtrudersShareTemperature setting
Getting the gcode output to put in extruder 2 temps.
Added UI support for manual extrusion with multiple extruders.
Merge branch 'development' of https://github.com/MatterHackers/MatterControl into development
Make sure we remember what material a mesh is using when we copy it.
Merge branch 'development' of https://github.com/MatterHackers/MatterControl into development
Alignment corrections.
Merge branch 'development' of https://github.com/MatterHackers/MatterControl into development
Adjusted library items.
resolved conflicts to merge