add methods very much like on vectors
remove sql server string
remove IDistance and implementations
always multiply with doubles
do some refactoring of Sample source code
fix dividing int by double resulting in zero
rename ISample to ISampleVector

This emphasizes the vector nature of the class.
rename difference to subtract on ISampleVector
discretize yes or no answers to 0, 1

Numerical values can better be used for calculating distances and averages. 0 means false, 1 means true.