[wip] added some point-wise convenience functions for FemTools

This isn't ready to merge yet, but it is needed for @ahmadia's gauges. 
- onElement test for ReferencElement objects
- pointwise getInverseMap for ElementMaps objects
- fixed some bugs in MultilevelProjections

We probably need to split the extensions to FemTools from the  multigrid changes. I did get the multilevel solvers updated so that they run in serial,  but I decided  to take a more direct  route to the supporting the gauge interpolation.
Yes, I think they all should.  Unless there's some other exception that is
more expressive for signalling these kinds of "pure virtual" functions for
abstract base classes.

On Tue, Nov 18, 2014 at 9:13 AM, Aron Ahmadia <notifications@github.com>
wrote:

> In src/FemTools.py:
>
> > @@ -2184,6 +2191,16 @@ def getInverseValues(self,
> >          given on the physical elements. Return the value of the inverse map.
> >          """
> >          pass
> > +    def getInverseValue(self,
> > +                        eN,
> > +                        x):
> > +        """
> > +        Evaluate the element inverse map at a point, x,
> > +        given in physical coorindates. Return the value of the inverse map, xi, in reference coordinates.
> > +
> > +        Note: The mapped point may not lie on the reference  element
> > +        """
> > +        pass
>
> Actually, shouldn't all of these functions raise NotImplementedErrors if
> called? Or am I missing something?
>
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