L2_semi_sg space added
Merge remote-tracking branch 'origin/new_devel' into new_devel
Make OutputAttachable methods return whether or not should the processing continue.
some testing
Fixes in NewtonSolver.
Additions to Newton:

- NewtonException
- vector storing residual and solution norms (using Output Attachable mixin)
- Add NewtonSolverConvergenceMeasurement enum &  newtonConverged global function (this should probably be improved).
Gcc fixes.
Rework NewtonSolver.
Fix hcurl example.
Add nonlinearity test example.
Testing & fixes.
Only add compiler flags for OpenMP for MSVC.
Merge remote-tracking branch 'upstream/devel' into new_devel

Conflicts:
	hermes2d/test_examples/CMakeLists.txt