Fix lines not attaching with a square angle (#176)

Center node graphics around 0,0 (move evrything 25 units left)

This works because the line attachement angles are calcualted as the
angle between 0,0 and the attachement point (all coordinates relative to
the node group).

Author: buehlefs

src/app/core/component/graph-display/graph-display.component.html

@@ -197,30 +197,30 @@ <h4 style="margin: 1em" *ngIf="showViewRelations">Pattern Language Relations</h4
             <rect data-click="nodeclick" data-link-handles="edges" height="50" rx="5" ry="5"
                   style="stroke:black;stroke-width:1;"
                   width="170"
-                  x="-60" y="-25">
+                  x="-85" y="-25">
             </rect>
             <!-- set both height and width values to define a maximum value for them -->
-            <image height="35" width="35" x="-55" y="-17.5" data-click="iconUrl" data-href="iconUrl"></image>
+            <image height="35" width="35" x="-80" y="-17.5" data-click="iconUrl" data-href="iconUrl"></image>
             <image *ngIf="enableDeletePattern" data-click="delete" data-content="patternLanguageId" class="node-action"
-                   width="10" x="80" y="-20" xlink:href="assets/delete.svg"/>
-            <image data-click="info" data-content="patternLanguageId" width="10" x="95"
+                   width="10" x="55" y="-20" xlink:href="assets/delete.svg"/>
+            <image data-click="info" data-content="patternLanguageId" width="10" x="70"
                    xlink:href="assets/Info_Simple_bw.svg" class="node-action"
                    y="-20"/>
             <text class="text" data-click="title" data-content="title" dominant-baseline="middle"
                   height="50" text-anchor="middle" style="font-weight: bold"
                   width="120"
-                  x="45"
+                  x="20"
                   y="0">
             </text>
             <text class="text cursive" data-click="patternLanguageName" *ngIf="showPatternLanguageName"
                   data-content="patternLanguageName"
                   dominant-baseline="middle"
                   height="50" text-anchor="middle"
                   width="120"
-                  x="45"
+                  x="20"
                   y="10">
             </text>
-            <g class="concrete-solutions-container" transform="translate(-60,25)"></g>
+            <g class="concrete-solutions-container" transform="translate(-85,25)"></g>
           </g>
 
           <g data-line-attachement-point="-9 0" data-template-type="marker"