Added DW_POINTER_TO_(U)LONGLONG and DW_(U)LONGLONG_TO_POINTER macros. This allows casting with intermediate (u)intptr_t cast to avoid compiler warnings on different systems. Use these macros where necessary in the code. Might need to check the compiler supports LONG LONG... since some compilers we support might not, like old versions of VisualAge C and Watcom.

# Set these here to change the version for all platforms
DW_MAJOR_VERSION=3
DW_MINOR_VERSION=1