(Orcc) CAL, Adding support for literal that are bigger than 64 bits,
backends should be adapted to support, in C backend it is sufficient to
change the printing ExprInt.
(frontend) Minor fixes for pull request #129

Add a test to avoid regression on the litterals size
Other minor fixes (code formatting)
Merge pull request #129 from orcc/big_integer_literals

Add support for 64 bits unsigned literals.

Close the pull request #129