Check and improve numerical compliance

[doe300]

For all mathematical functions, check and improve (if necessary) the numerical compliance.
Update the file doc/NumericalCompliance.md accordingly.

List of useful sources:

• http://gams.nist.gov/cgi-bin/serve.cgi/ (especially section C)
• http://www.netlib.org/fdlibm/
• http://www.netlib.org/cephes/qlibdoc.html
• https://www.johndcook.com/blog/stand_alone_code/
• https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html