Fix misspellings in various modules.

src/plugins/tools/net_tracer/db_plugin/dbNetTracer.cc

@@ -1067,7 +1067,7 @@ NetTracer::trace (const db::Layout &layout, const db::Cell &cell, const NetTrace
           db::Box b = c->first.bbox ();
           double a = c->first.shape ().area ();
 
-          //  The ratio theshold of 20 for box/shape area was determined empirically
+          //  The ratio threshold of 20 for box/shape area was determined empirically
           if ((combined_box + b).area () > (asum + a) * 20.0) {
             ++c;
             --n;
@@ -1221,7 +1221,7 @@ NetTracer::trace (const db::Layout &layout, const db::Cell &cell, const NetTrace
       const NetTracerShape *stop = &m_shapes_graph.find (m_stop_shape)->first;
       const NetTracerShape *start = &m_shapes_graph.find (m_start_shape)->first;
 
-      //  find the shortest path with Dijkstras algorithm
+      //  find the shortest path with Dijkstra's algorithm
 
       std::map<const NetTracerShape *, const NetTracerShape *> previous;
       std::map<const NetTracerShape *, size_t> cost;

src/plugins/tools/net_tracer/lay_plugin/layNetTracerDialog.cc

@@ -824,7 +824,7 @@ NetTracerDialog::update_info ()
             db::coord_traits<db::Coord>::area_type area = 0;
             db::coord_traits<db::Coord>::perimeter_type perimeter = 0;
 
-            //  Despite merging, a multitude of seperate non-touching polygons can exist.
+            //  Despite merging, a multitude of separate non-touching polygons can exist.
             for (std::vector <db::Polygon>::iterator j = merged.begin (); j != merged.end (); ++j) {
               //  Sum area 
               area += j->area ();

src/plugins/tools/view_25d/lay_plugin/layD25ViewUtils.cc

@@ -180,7 +180,7 @@ normalize_scene_trans (const QMatrix4x4 &cam_trans, QVector3D &displacement, dou
   //
   //  this is image invariant (only x,y results are considered) against changes of s (s->s') if
   //
-  //    1.) (p*d*s+z)/s = (p*d'*s'+z)/s'  (because x and y will be devided by this value)
+  //    1.) (p*d*s+z)/s = (p*d'*s'+z)/s'  (because x and y will be divided by this value)
   //    2.) (M*d*s+t)/s = (M*d'*s'+t)/s'  for  [x] and [y]
   //
   //  or

src/plugins/tools/view_25d/lay_plugin/layD25ViewWidget.cc

@@ -309,7 +309,7 @@ D25ViewWidget::keyPressEvent (QKeyEvent *event)
 
     if (! top_view () && (event->modifiers () & Qt::ControlModifier) != 0) {
 
-      //  Ctrl + left/right changes azumith
+      //  Ctrl + left/right changes azimuths
 
       double d = (event->key () == Qt::Key_Right ? 2 : -2);
 

src/plugins/tools/xor/lay_plugin/layXORToolDialog.cc

@@ -806,7 +806,7 @@ XORWorker::do_perform_deep (const XORTask *xor_task)
         rr.size (((*t + 1) / 2), (unsigned int)2, false);
       }
 
-      //  TODO: no clipping for hieararchical mode yet
+      //  TODO: no clipping for hierarchical mode yet
       mp_job->issue_region (tol_index, xor_task->layer_index (), rr);
 
       mp_job->add_results (xor_task->lp (), *t, rr.count (), xor_task->ix (), xor_task->iy ());