adjusted LayeredVolume-interface to take raster files from bottom to top
changed static methods in MeshLayerMapper to non-static
slightly changed creation of static subsurface layers
moved raster i/o to FileIO/AsciiRasterInterface
moved raster interpolation and raster extend test to raster class
When giving a custom comparison in std::sort use < as operator (not <=).

This fixes crashes in debug mode (especially in some tests) in which case the
runtime checks this rule and quits execution on violation.
Updated gtest to 1.7
Added gtest license.
Reintroduced scripts/packaging/.DS_Store which is needed for mac packaging.
Fixed logo path for mac packaging.
Fixed wrong support point index at start and end point.
Merge pull request #471 from bilke/sort-crash

When giving a custom comparison in std::sort use < as operator (not <=).
Merge pull request #472 from bilke/ctest-1.7

Update gtest to 1.7
Merge pull request #463 from endJunction/SkeletonProjectData

Skeleton project data
Merge pull request #473 from bilke/fix-interpolation

Fixed wrong support point index at start and end point.
[PL] GroundwaterFlow.h -> GroundwaterFlowProcess.h.
Merge pull request #474 from TomFischer/RenameGroundwaterFlowProcess

[PL] GroundwaterFlow.h -> GroundwaterFlowProcess.h.
Disabled warning C4996 on MSVC.

This warning appears in std::fill_n and can be ignored.
reworked prims-layer-generation to work from top to bottom and prefer older (lower) layers in cases of conflicting information
simplyfied layerMapping method to only handle single layered meshes