Fixed include file errors and added const to vars

[wgoulet]

Hi,

I tried using your crypto library on my Arduino Uno Rev3 and found that the code wouldn't compile. This request contains the minor changes I made to make the test cases pass.

Note that I didn't fully test the library yet, but if I find any more issues I'll create another request.

Thanks,
Walter

[spaniakos]

hello , thanks for the commit
i only have one disagreement.
#include "Print.h"
#include < Print.h >

this change.
because in intel galileo a unique print.h is required i would ask you if you can find the reserved word for your microcntroller
for intel galileo is : ARDUINO_X86
if you find that i can add some board specific code like my own and will merge the changes :D
thanks for the effort.