Fixes.
Finalize OptimumSelector.
Update of selectors, drop CONV_EXT parameter & update examples accordingly.
Update of DP cache.
Make some mixins methods virtual.
Progress on mixins, add reporting of DG cache hits and misses.
Progress on Adaptivity.
Fix Newton.
Intel compiler fixes.
Additions because of NIST benchmarks for FEMTEC.
A fix in Essential BCs.
Add acoustic example for FEMTEC presentation.
some testing
some changes
Merge remote-tracking branch 'lukas/devel' into new_devel

Conflicts:
	hermes2d/src/adapt/error_calculator.cpp
	hermes2d/test_examples/CMakeLists.txt
minor changes