add TemplateIsoparametric
define FeQUAD4
add tests of FeQUAD4 with Eigen
[NL] Update from samplingLevel to integrationOrder.
[NLT] Update eigen include dir as in 4b9bfd.
[NL] Remove unnecessary setter call from ctor.
[NL] Rename IntegrationType to IntegrationMethod.

Use it in the NumLibFemIsoQuad4Test instead of auto.
[NL] Remove internal integration method object.
[TNL] Move up integration_method into test fixture.
[NL] Rename resetMeshElement() to setMeshElement().
[NL] Remove unnecessary explicit keyword.
[TNL] Additionally check number of integration points.
Merge pull request #233 from endJunction/feature-IsoparaFE

Isoparametric finite quad4 element.