Improve dialog layout and fix UI policy issues with all of the dialog
boxes in the Gerbview and Pcbnew code paths.
Updated the use of component to footprint where appropriate.
This patch enables math expression evaluation for most of the text input
controls in pcbnew.
NEW: pcbnew text input controls are able to evaluate simple
mathematical expressions, including distance units (e.g. 5.0+(2*1.2mm)).