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.
There are two distinct procedures starting on L98, one uses the other. L99 isn't directly multiplying the contents current result by secretMultiplier, it's multiplying by the result of (k*r+hash %n).

So overall on L98: s = (k^-1%n)*(k*r +hash %n) where the EcMath is doing the calculations between parenthesis, and using results of the nested one. 

R is found by using another EcMath class, see L92, but since R needs to be used in a comparison before S can be calculated, I didn't nest that calculation in the mul() on L101.