Fix MKS elasticity test

Fix MKS elasticity by removing the boundary cell where the assumption
of periodic boundary conditions is not valid. The tolerance was also
increased slightly.
Fix Boundary Conditions and resize_coeff

Fix issue #67

Fix the boundary conditions for the ElasticFEModel to have the
macroscopic strain value for any size microstructure. The previous
boundary conditions were incorrect and were creating an error with
re-sized influence coefficients.

Fix zero padding of the constant coefficients. For the constant valued
influence coefficients, the k0 value stays the same regardless of the
re-sizing.
Fix doctest verbose issue

Fix doctest by including directives to ignore the output from sfepy
generated while computing the strain field.
Add nosetests for resize_coeff method

Address issue #67

Add nosetests for resize_coeff to ensure that the method doesn't break
when added functionality to the package.