Blurb::
Scales mutation across range of parameter
Description::
The mutation_scale is a fraction in the range [0, 1] and is meant to help 
control the amount of variation that takes place when a variable is mutated.
Its behavior depends on the selected \c mutation_type. For \c offset_normal
and \c offset_cauchy, \c mutation_scale is multipled by the range of the 
variable being mutated to obtain the standard deviation of the offset. For
\c offset_uniform, the range of possible deviation amounts is +/- 1/2 * 
(mutation_scale * variable range). 
Topics::
Examples::
Theory::
Faq::
See_Also::	
