Remove PointerCalculatorFactory

* clean up pointer calculator tests
* move construction of shared_ptr into static PointerCalculator::create
Cleanup pointercalculator class, added override spec
Merge pull request #155 from bastih/feature/remove_pointercalc_factory

PointerCalculator cleanup
Remove unused tracking or result sorting
Improve url decoding to involve fewer steps, and less copying
Merge pull request #157 from bastih/master

Improve url decoding to involve fewer steps, and less copying
Merge remote-tracking branch 'origin/master' into feature/value_scan_for_delta