Adaptive refinement on enriched cells without well.
Adaptive integration - distance criterion.
Improve text output of run method.
Fix bitwise operator in flags comparision.
Adaptivity test with characteristic function of a well.
Adaptive integration, destructor bug.

- fix bug if make_grid was called more times
- randomize well center in adaptive_integration test
- improve adaptive_integration
ESCO article LaTeX source added.
Gnuplot scripts.
Add empty quadrature, output_dir getter, output refined elements.
ESCO article.
Improve adaptive integration test.
New version created.