[FEATURE] SignalToNoiseEstimatorMedianRapid

- A SignalToNoise estimator based on median calculation but
  significantly faster than the SignalToNoiseEstimatorMedian
[TEST] add test for SignalToNoiseEstimatorMedianRapid
[FEATURE] PeakPickerMaxima

- maxima-searching PeakPicker based on PeakPickerHiRes
- this peak picker uses a cleaner interface and the new rapid signal to
  noise estimation
[FIX] performance improvement

- replace std::map with two doubles to keep track of current status of
  peak
[INTERNAL] move code to cpp file
[TEST] remove test to show numerically compatibility

- remove test to show numerically compatibility between the
  SignalToNoiseEstimatorMedian and rapid version
- the test took too long to execute, did not contribute significantly to
  unit testing
[FIX] switch to new Eigen spline

- use Eigen splines instead of gsl
[TEST] re-add old test files

- add new test files (after change by GSL removal)
[FIX] adopt tests for Eigen splines
[FEATURE] switch to Wm5 splines
[TEST] adopt tests to Wm5 splines
[TEST] add further tests
[TEST] Speedtest

fix speedcheck
[API] add cpp for CubicSpline2d
[API] DLL macro added
[TEST] CubicSpline2d test split in several sections
[NOP] uncrustified
[NOP] uncrustified
[NOP] indention changed
[INTERNAL] template remnants removed