started on z-module: classes Z and Tipper

Signed-off-by: LK <LK@uni>
Z module mostly done; get/set/rotate/invert for Z and Tipper classes; todo: check for None/non-existing arrays/attributes; todo: functions, ; todo: remove distortion/static shift

Signed-off-by: LK <LK@uni>
Z module: remove_ss and remove_distortion missing

Signed-off-by: LK <LK@uni>
Z module: added dummmies for invariants,resistivity, and ellipticity

Signed-off-by: LK <LK@uni>
Z class: remove static shift done

Signed-off-by: LK <LK@uni>
Z class: remove distortion  done (incl. error propagation using 1-norm)

Signed-off-by: LK <LK@uni>
Edi class: reduced number of attributes, added methods, esp. get/set_<value> ones

Signed-off-by: LK <LK@uni>
started pt module with PhaseTensor class

Signed-off-by: LK <LK@uni>
PhaseTensor royghly done...checkk all error propagations

Signed-off-by: LK <LK@uni>
PT imports work consistently - to check: propagation of errors in Z (var(determinant) for calculation of D.I)

Signed-off-by: LK <LK@uni>
added module calculator.py for standard calculations (e.g. error propagation)...corrected z.py for error calculation

Signed-off-by: LK <LK@uni>
defined PT class and methods. Reading od z-arrays into PT object works. Methods to be written, errors corrected (internal use of standard deviation instead of VAR). Variables VAR only used for in- and output to/from EDI files and objects (in the respective dictionaries)

Signed-off-by: LK <LK@uni>
moved rotation to calculator.py...adapted Z and EDI classes

Signed-off-by: LK <LK@uni>
rotation of matrices and vectors incl. error propagation in calculator.py done (and corrected)

Signed-off-by: LK <LK@uni>
propagate_error_rect2polar corrected...still: zerror amplitude  is not properly reflected in PTerror amplitude

Signed-off-by: LK <LK@uni>
strated "geometry" module

Signed-off-by: LK <LK@uni>