MacOSX 64-Bit Tests won't build

In MacOSX 64-Bit there is a differentiation between ::int64_t (which is long long) and a "long"-value, even though they have the same width.

If you pass a big value it is interpreted as "long"-value and not as a "long long"-value. Therefore the functions operator<<(int64_t) and operator<<(uint64_t) are ambiguous.

We may want to check if a similar issue exists on other operating systems.

--------------------

StringOutputStreamTest.cpp:71:22: 
error: use of overloaded operator '<<' is ambiguous (with operand types 'capu::StringOutputStream' and 'long') outputStream << 0x6464646432323232;