Capitalize beginning of tooltips + Typos

Capitalized all remaining uncapitalized tooltips. 
+ Fixed typo in instantiate() function. Shouldn't have any repercussions on the code, AFAICT. 
+ other typos

src/Mod/Cam/App/SpringbackCorrection.cpp

@@ -278,7 +278,7 @@ bool SpringbackCorrection::CalcCurv()
 
 
 
-        FacePntVector.resize(innerpoints);  // stores inner-points and sourrounding edges-distances
+        FacePntVector.resize(innerpoints);  // stores inner-points and surrounding edges-distances
 
         // explores the edges of the face ----------------------
         for (aExpEdge.Init(aFace,TopAbs_EDGE);aExpEdge.More();aExpEdge.Next())

src/Mod/Cam/App/SpringbackCorrection.h

@@ -82,9 +82,9 @@ struct MeshPnt
 /** @brief a struct for computing the maximum and minimum curvature-radius
            of a single mesh-point
     @param pnt        mesh-point
-    @param distances  distance-vector to all sourrounding edges
-    @param MinEdgeOff minimum curvature-radii of sourrounding edges
-    @param MaxEdgeOff maximum curvature-radii of sourrounding edges
+    @param distances  distance-vector to all surrounding edges
+    @param MinEdgeOff minimum curvature-radii of surrounding edges
+    @param MaxEdgeOff maximum curvature-radii of surrounding edges
 */
 struct FacePnt
 {