\section ms_64bits Adds support for 64 bits integer

There has been many request to add support for 64 bits integer. Use case for this are:

- time is nowdays commonly represented with a 64 bits integer

- 64 bits integer are frequently used as primary key id in many systems

Plans to add support is:

- must be optional, a configuration option since not all platforms provides 64 bits integer types.

- move definition of Int and UInt from forwards.h to config.h, with the required platform magic.

- C++ defines no standard to define 64 bits integer. Rely on msvc extension, and long long type that

is widely supported.