Fixes compilation error with GCC 5.x:
c_src/double-conversion/bignum.cc:102:6: error: assuming signed overflow does not occur when assuming that (X + c) < X is always false [-Werror=strict-overflow]
void Bignum::AssignDecimalString(Vector<const char> value) {
^
cc1plus: all warnings being treated as errors
While using rebar's dependency management was surprisingly easy it
broke apps that tried to build Jiffy as a dependency due to relative
path #includes.
This also fixes a few other issues. Most notably it removes the use of
the ECMAScript compatible encoding due to JSON's lack of support for +/-
Inf and NaN.