Code improvement fixes.

Restore 'const' status of input to copy-constructor.

Specify calling of base-class move constructor in derived-class move constructor.

Copy constructors for Grid1D through UnitConvert (list classes in alphabetical order) are not correct.  Function prototypes were changed, but implementation is not yet valid.

Removed move-assignment operators.  StackOverflow answer (http://stackoverflow.com/a/14504109) states that my implementation of the copy-assignment operator using the copy-and-swap idiom works for both lvalues and rvalues.  This causes compiler confusion when both a copy-constructor and move-constructor are defined.  Only having a copy-assignment operator using the copy-and-swap idiom meets the compiler needs and avoids confusion.