Revised documentation.

This is for #72.
Fixed typo in documentation.
Replaced min with smoothMin.

This is for #72.
Added test for Medium.nX==2

This is for #72.
Introduced Utilities.Psychometrics.Constants

This is for #72.
It was done to use consistent values throughout the library.
Revised documentation.

This is for #72
Corrected html syntax.

This is for #72.