Work on Shapeset - add L2ShapesetTaylor and polish others.
Fix behavior of linearizer upper bound on levels - take into account the bi-linearity of linear functions on quadrilaterals.
Add MeshFunction<Scalar>::add.
Implement second order Taylor basis.
Add some skeleton of future Postprocessing area of Hermes.
	- implement the VertexBasedLimiter according to Dmitri Kuzmin
Testing of DG limiting.
Add miscelaneous files to .gitignore.
Make Hermes::showInternalWarnings reflect Release/Debug build.
Make ExactSolution class calculate integration order - instead of using the maximum one.
Update of views - make set_title use variable arglist, delete unused code.
Add VertexBasedLimiter example.
Include <limits>.
A fix wrt. recent changes.
Implement (not completely, not tested) the rest of Kuzmin's slope limiting for quadratic elements
	- use it in the example (works).
Make some Solution - methods available outside.
Add centroids of elements to global.h.
Move ELEMENT_DELTA_X to global.h.
Progress on Limiting.
A fix in the Limiter.
Use explicit time stepping in the limiter example.