Fix typos in various files [skip-ci]

Found via `codespell 2.0.dev0`  
```
codespell -q 2 -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/Import/App/dxf.cpp

@@ -30,7 +30,7 @@ Base::Vector3d toVector3d(const double* a)
 }
 
 CDxfWrite::CDxfWrite(const char* filepath) :
-//TODO: these should probably be parms in config file
+//TODO: these should probably be parameters in config file
 //handles:
 //boilerplate 0 - A00
 //used by dxf.cpp A01 - FFFE