Improve dialog layout and fix UI policy issues with all of the dialog
boxes in the common, 3D viewer, CvPcb, and Eeschema code paths.
Updated the use of component to symbol.
* if the current select plugin is the github plugin, one can select some of these libraries and add them to the table
* if the current select plugin is the kicad plugin, one can select some of these libraries and download them to make alocal copy.
They can added to the table after they are downloaded.
jean-pierre charras
Wayne Stambaugh
Baranovskiy Konstantin