Ecmath

Added an EcMath class, which accepts a numeric value or a PointInterface.
Added an interface, covering add(), mul(), getDouble(), mod(), and cmp(), and result(). 

There are tests for the EcMath class, mainly just asserting some operations like (k+k)*G = (k*G)+(k*G). 
Test.php has some examples of usage. (Private/Public classes are not the classes used in this library)

The library tolerates you trying to add an integer to a point, by carrying out the point multiplication when required. 
It will throw an exception if you try to do something impossible, like multiplying two points together.

I haven't added an equals() function, like the Point and Math class both have, though I will probably add this shortly.  Also want to refactor the Math, EcMath, and Crypto components into namespaces, after we discuss it.
It would help keep things neat if you're using the DebugDecorator. Math doesn't already deal with points, but makes sense all the same. 

The Generator needs to be supplied, so $math->getEcMath($d, $G)? Or what about in EccFactory?