maintain size of datatypes in XS cross-platform

Use the C99 types `uint16_t` and `uint32_t` instead of unsigned short and unsigned longs for the size-sensitive datatypes in AM.xs. Hopefully this will make things work on *nix 64-bit. See http://stackoverflow.com/questions/384502/what-is-the-bit-size-of-long-on-64-bit-windows. See issue #2.

These types as used in AM could no longer be called `ULONG` and `USHORT`,
since these are already defined in windef.h. Thus, they are renamed
`AM_SHORT` and `AM_LONG`.

Note that now C99 is required to compile AM, though this is not yet made explicit.
updated Changes
satisfy release tests and update Changes
New CPAN release of Algorithm-AM - v2.36

    remove given/when (which trigger 'experimental' warnings)
    better handling of project files
    line directives added to ginormous eval statement
    add methods to Project for adding data and test items
    use C99 datatypes in AM.xs to ensure correct bit sizes