add functions:

 * ComplexMatrix::isHermitian
 * ComplexMatrix::isEqual
 * ComplexVector::isEqual
 * Complex::isEqual
add functions:

 * ComplexMatrix::isUnitary()
 * ComplexMatrix::Identity()
split quash into library and executable
add stubs for double-slit experiment
remove trailing zeros when setting precision as well
add functions:

 * ComplexVector::isNormalize()
 * ComplexVector::normalize()
add double slit experiment code
decoupling data and functions to better implement 'interfaces'.

First step: class Real
decoupling #2: class Complex
decoupling #3: ComplexVector
decoupling #4: ComplexMatrix

 * likely to get changed again
introduce proper constructors in exchange for *_from* functions

 * makes using Real and Complex more pleasant
remove helpers from header