Merge pull request #6 from endJunction/2dGroundWaterFlow

Thanks for your work, Dima!
[OGSLib] Removed old OGS-5 code.
[2dGW] Store bc valuesin vector and applying it to the sys. of lin. eqs.
[MeshGeoToolsLib] Fix calculation of search length.

In case of aquidistant meshes the expression sum_of_sqr - (sum*sum)/edge_cnt can get negative due to numerical calculation. The root of a negative value is not computable in real numbers.
[2dGWF] Add boundary condition to all nodes along polyline.
[ML] Decrease Lis solver default tolerance.

This resolves issues for to high tolerance when applied to matrices with penalty terms from Dirichlet BC.
Add assertion for searching nodes along a polyline algorithm.
Even more WIP