correct path
add helper functions to release memory
add DiscreteLib in CMake
add TestDiscreteLib
save progress in DiscreteLib
need to include some other headers
add DiscreteLib in Doxyfile
save progress in DiscreteLib
save
add DoF object
save progress. Test cases are working
Remove extra namespace specialization.
Take LisLinearSystem include in USE_LIS guards.
Extract part of TestLinearSystem test to 2Ddiffusion.

This removes gtest and LIS dependencies and simplifies code coverage.
Add coverage make target for 2Ddiffusion.
Remove ghost point functions. All unused.
Remove other unused functions from DofEquationTable.
Remove DoF/SequentialEquationStorage.
Remove IEquationStorage::size and hasEquationID.
Remove RandomEquationIdStorage::pointID.