test_fcl_math fails on Windows 64 bit due to non-portable use of long

[sherm1]

Visual C++ defines long to be 32 bits even in 64 bit mode while gcc and clang make it 64 bits. The standard permits this and as a result the long type is generally useless and causes portability problems.
long long is 64 bits on all of these compilers. Generally we can avoid trouble by using the C++11 <cstdint> types like uint64_t when we're depending on a particular number of bits.

The test_fcl_math regression test fails on Win64 because it assumes here that a 60-bit bitset can be returned in an unsigned long. boost::dynamic_bitset doesn't support long long but std::bitset does.

I'm working on removing dynamic_bitset and will fix this issue with that PR.