Move ElementTraits classes to a new header file.
Reformatted lines of code.

This is to make easier to read on GitHub.
Move the 'MultiArray' class to another file.
Reformatted lines of code.
Add copyright notice.
Throw exception instead of exiting program.
Fix the assignment operator for wrapped data.
Include header in alphabetical order.
Remove inclusion of 'vld.h'.
Fix header inclusion.
It is unnecessary to throw an exception for the assignment operator.

However it is clear that there is room for improvement regarding the
assignment operator.
Fix message content when throwing exception.
Merge pull request #107 from DO-CV/maint-fix-break-down-multiarray-hpp

[MAINT] Divide 'Multiarray.hpp' into several headers.