Elements: DomainException when trying to shrink a value which does not
belongs to the values of the domain
Integer: DomainException when trying to shrink a value outside of the
boundaries of the domain
Natural: DomainException when trying to shrink a value outside of the boundaries of the domain
String: DomainException when trying to shrink a value outside of the boundaries of the domain

Improved the Generator\String::contains/1 because it was not checking
if the argument was actually a string
Tuple: DomainException when trying to shrink a tuple which does not
match the tuple of the domains
Fighting type juggling

Since (false == '') we were not stopping the shrinking of a String to
the '' but to false.
Vector: DomainException when trying to shrink a Vector which does not
belong to the domain
From " to '