[lib] ALUConformGrid< 2, 2 > -> ALUGrid< 2, 2, simplex, conforming >
[linearelliptic.testcases.base] added first draft
[linearelliptic.testcases.ESV2007] added first draft
[tests.linearelliptic] added first draft of Tests::EocStudyBase

This class will take most of the work off of the implementor of a
Stuff::Common::ConvergenceStudy, given that the discretization is a
ContainerBasedDefault.
[tests.linearelliptic-swipdg] added first draft

This is basically a copy from dune-gdt.
[cmake] added tests