New class for the number

This is another attempt to further encapsulate the data,
the core number class is now created, but not in use yet.
Added some operators and improved abstraction

Added some of the usual operators: ==, < and friends
as well as: *=, /=, +=, -= and their binary versions
The constructor should now also keep things in check with (&= 15)
Much better encapsulation

Hexdecbin now uses the new number class and every thing is now much
more abstracted from the end user.
Merge pull request #3 from physcat/number

Number