Added viewbox and mm units to Drawing templates

src/Mod/Drawing/Templates/A3_Landscape.svg

@@ -9,8 +9,9 @@
    xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
    xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
    xmlns:freecad="http://sourceforge.net/apps/mediawiki/free-cad/index.php?title=Svg_Namespace"
-   width="420"
-   height="297"
+   width="420mm"
+   height="297mm"
+   viewBox="0 0 420 297"
    version="1.1"
    id="svg2"
    sodipodi:version="0.32"
@@ -576,9 +577,6 @@
      bordercolor="#666666"
      pagecolor="#ffffff"
      id="base"
-     inkscape:zoom="1.7101889"
-     inkscape:cx="254.10366"
-     inkscape:cy="146.94782"
      inkscape:window-x="0"
      inkscape:window-y="20"
      inkscape:current-layer="svg2"

src/Mod/Drawing/Templates/A4_Landscape.svg

@@ -8,8 +8,9 @@
    xmlns:xlink="http://www.w3.org/1999/xlink"
    xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
    xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
-   width="297"
-   height="210"
+   width="297mm"
+   height="210mm"
+   viewBox="0 0 297 210"
    version="1.1"
    id="svg2"
    sodipodi:version="0.32"
@@ -903,9 +904,6 @@
      bordercolor="#666666"
      pagecolor="#ffffff"
      id="base"
-     inkscape:zoom="3.5"
-     inkscape:cx="119.25908"
-     inkscape:cy="0.84879944"
      inkscape:window-x="0"
      inkscape:window-y="22"
      inkscape:current-layer="svg2"

src/Mod/Drawing/Templates/A4_Simple.svg

@@ -7,7 +7,8 @@
      version="1.1" 
 	 baseProfile="full"
      width="297mm" 
-	 height="420mm">
+	 height="420mm" 
+	 viewBox="0 0 297 420">
 	 
 <!-- DrawingContent -->