review of the code: minor changes of code and documentation
code revision: minor changes
Merge remote-tracking branch 'remotes/upstream/master' into issue72_reviewOfPsychometry
add psychometricsConstants.mo
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.
Accepted new reference result.
Merge pull request #80 from iea-annex60/issue72_reviewOfPsychometry

Issue72 review of psychometry