STLSoft 1.9.88: all-integer handling for comstl::variant

The latest release (1.9.88) of STLSoft contains an updated comstl::variant class. The previous version had three constructors for integer types: short, int and long. The new version has six constructors for integer types: sint8_t, uint8_t, sint16_t, uint16_t, sint32_t, uint32_t. (It also has short, int and long constructors for those compilers that have distinct types against the 8/16/32-fixed integer types; see chapter 29 of Imperfect C++)