Fix typos and some trailing whitespace

Found via:  
```
codespell -q 3 -L aci,ake,aline,alle,alledges,alocation,als,ang,anid,ba,beginn,behaviour,bloaded,byteorder,calculater,cancelled,cancelling,cas,cascade,centimetre,childs,colour,colours,commen,currenty,dof,doubleclick,dum,eiter,elemente,feld,freez,hist,iff,indicies,initialisation,initialise,initialised,initialises,initialisiert,ist,kilometre,lod,mantatory,methode,metres,millimetre,modell,nd,noe,normale,normaly,nto,numer,oder,orgin,orginx,orginy,ot,pard,pres,programm,que,recurrance,rougly,seperator,serie,sinc,strack,substraction,te,thist,thru,tread,uint,unter,vertexes,wallthickness,whitespaces -S ./.git,*.po,*.ts,./ChangeLog.txt,./src/3rdParty,./src/Mod/Assembly/App/opendcm,./src/CXX,./src/zipios++,./src/Base/swig*,./src/Mod/Robot/App/kdl_cp,./src/Mod/Import/App/SCL,./src/WindowsInstaller,./src/Doc/FreeCAD.uml
```

src/Mod/Arch/OfflineRenderingUtils.py

@@ -362,7 +362,7 @@ def render(outputfile,scene=None,camera=None,zoom=False,width=400,height=300,bac
 def buildScene(objects,colors=None):
 
     """buildScene(objects,colors=None): builds a coin node from a given list of FreeCAD
-    objects. Optional colors argument can be a dicionary of objName:ShapeColorTuple
+    objects. Optional colors argument can be a dictionary of objName:ShapeColorTuple
     or obj:DiffuseColorList pairs."""
 
     from pivy import coin

src/Mod/Arch/importIFCHelper.py

@@ -433,7 +433,7 @@ def buildRelProperties(ifcfile):
 
 
 def getIfcPropertySets(ifcfile, pid):
-    """Returns a dicionary of {pset_id:[prop_id, prop_id...]} for an IFC object"""
+    """Returns a dictionary of {pset_id:[prop_id, prop_id...]} for an IFC object"""
 
     # get psets for this pid
     psets = {}