Node searching methods need to know whether they process only base nodes or all nodes including nonlinear
calculate node distance in element and mesh
support node distance in HeuristicSearchLength
rename the variable to make it self explainable
improve documentation
added dialog for mesh writer options
adjusted vtu-interface to support binary and append flags
added support for mesh name in VtkMeshConverter
added dialogue to select vtk data writer options
adjusted mesh view to use new dialogue
removed comments and unnecessary code
formatting
correct handling of empty path
Fixed VtuInterface ascii writing.

Save mesh dialog compression availability check.
added encode flag for appended data
Merge pull request #509 from norihiro-w/node-search-nonlinear

Extend node searching stuff to handle nonlinear nodes
removed void param
changed distance arrays to pairs
added documentation for variables
Merge pull request #522 from rinkk/MeshWriterConfig

Mesh writer config. Extend VtuInterface.